Statistics Word Problems
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There are four choices of apple and orange. How many combinations are there?

Three apples cost as much as four pears. 3 pears cost as much as 2 oranges. how many apples cost as much as 72 oranges?

Have 8 navy blue socks, 5 black socks. what is the porbability of two socks matching?

29 out of 200 chickens contaminated. If chicken infected, test will return positive 80% of the time. If chicken not infected, test will return "false" positive 5% of the time. If test is positive, what is the probability that chicken is actually infected?

Two cards are simultaneously drawn from an ordinary deck. What is the probability that they are not both the same suit?

A cheese pizza can be ordered with some, all, or none of the following toppings: sausage, pepperoni, ham, peppers, mushrooms, olives, anchovies, pineapple, and onion. How many different variations are available for ordering a pizza?

Drawing 3 cards that are all aces from a deck of cards?

Selena has 4 exams ( A, B, C,D) to study for this week. How many different ways can she arrange her study time.

After 4 games, Rita`s average bowling score was 99. What score must she bowl on her next game to increase her bowling average to 100?

How many 3 topping pizzas could be made if you have 10 toppings to choose from?

The average of three numbers is 20. If one of those numbers is 15, what is the average of the other two numbers?

Renee ran the marathon in 3 hours. If she ran 10 miles in the first hour, what was her average speed, in miles per hour, for the remaining 16 miles?

Lisa is planning the seating for a head table at a gala. The eight speakers will all be seated along one side of the table. Richard wants to be sit beside Hang, and lisa knows that Thomas and Lily should not be seated together, as they have just broken up. In how many ways can Lisa make up the seating plan?

Kate has a red pair of shoes, a blue pair of shoes, and a green pair of shoes. She has a yellow and an orange purse. How many different ways can she wear one pair of shoes and one pair of purse?

Jim sells soup at his stand. He sells lentil, split pea, and navy bean soup. They also come in four different sizes. How many different types of soup does he sell?

An airplane has two independent alternators to provide electrical power. The probability that a given alternator wil fail on a one hour flight is .02. What is the probability that a) both will fail b) neither will fail c) one or the other will fail?

What is the probability of drawing two cards that are not in the same suit when drawn simultaneously?

A student notices that if he is late for college on one day, he is three times more likely to be late on the next day. If he is early on one day, he is equally likely to be early or late on the next day. Draw a tree diagram to show all the possible outcomes for three successive days. ( Assume that the student was early on the day before the 3 days under consideration.)

In how many different ways can 11 different books be distributed to Abe, Carol and Ben if each is to receive at least 2 books?

There are 3 sky blue marbles and 3 hot pink marbles in a bag. What is the probability that I will draw out 1 sky blue marble, and 1 hot pink marble?

You have twentytwo socks. Fortunately, you only have two colors white and blue. How many socks do you need to draw before you get a matching pair?

A spinner is divided into five equal sections numbered 1 through 5. predict how many times out of 240 spins the spinner is most likely to stop on an odd number.

There are 3 bags of apples, one has two green apples, one has two red apples and one has 1 green and 1 red apple. All three bags are mislabeled. You may look at only one apple from any one of the bags. Which bag should you select from to be sure you can determine the contents of all three bags?

If the chances of snow or sleet last Saturday was three out of ten and the chance of snow or sleet this Saturday was four out of ten what were the chances of snow or sleet happening both weeks?

During a root enzyme experiment, Grace determined the dry weight of mustard roots so she could make some calculations. These were pretty small mustard plants so she had to use a good balance to get the data. She measured one set (A) of roots and obtained masses of 0.06, 0.09, 0.08, 0.05, and 0.05 grams. Another set (B) had masses of 0.1, 0.11, 0.09, 0.11, and 0.04 grams. Which set had the greatest average mass?

In a fair game (50/50 chance of winning) two guys bet $100 each. The first one to win 6 games takes the pot. They decided to stop when A had won 5 games and B had won 3 games. How should they distribute the pot.

What is the probability of obtaining a sum of at least 6 when rolling a pair of dice?

If there are 25 names in a hat, 15 girl’s names and 10 boy’s names, what is the probability that a name drawn at random will be I. a girl’s name II. a boy’s name III. not a girl’s name IV. not a boy’s name

A container of jelly beans contains 50 buttered popcorn, 65 strawberry, 80 cinnamon, and 45 orange. How many must be selected to guarantee that you have at least 30 of one flavor?

Each of a sample of 184 residents were asked how much they spent of lottery tickets. 124 responded with $0. The mean of the remaining was $20. The largest expenditure was $228. What is the mean of the 184 data points?

John wants to paint four rooms in his house, each a different color and he may choose from seven different colors of paint. How many color combinations are possible for the four rooms?

Find the IQ score separating the top 85% from the others. Assume adults that have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 15.

A pair of dice are rolled and their sum is recorded. How many different ways aret there if you roll the pair of dice 8 times.

At the picnic, there is a plate of 3 dill pickles, 2 bread and butter pickles, and 1 sweet pickle. What is the probability that Shawn will randomly pick a dill pickle and then a sweet pickle to eat?

Margo’s bank balances were: $ 20 on Monday, $ 5 on Tuesday, $ 0 on Wednesday, $  14 on Thursday, and $  10 on Friday. What were the Mean and Median Balances for the week? a. Mean _____________ b. Median ____________

The temperatures for last week in Columbus, Ohio, were the following: 12 on Monday, 3 on Tuesday, 5 on Wednesday, 10 on Thursday, and 10 on Friday. What were the Mean and Median temperatures for the week? a. Mean _____________ b. Median ____________

A drawer contains 8 black socks, 18 green socks, 12 blue socks and 11 brown socks. If the drawer is in a darkened room, how many socks must you grab to be certain you have four matching socks.

25 employees were surveyed at AIU. 7 had less than 2 years, 11 had over 2 years and 7 had 5 years or more. What is the mean, median and mode?

A mall has 12 clothing stores, 9 shoe stores and 5 electrical stores. In how many ways can a person shopping at this mall go to 5 clothing stores, 4 shoe stores and 3 electronic stores?

There are three sections of science class available at the convinient times for student. There is 24% chance from Professor Praful to give final exam, 15% chance for professor Ron, and 8% chance for Professor Sam to give final exam. At other times there are two maths classes, and in those the probability to give final exam is 2% and 10%. Find the probability the student randomly chooses one math and science take final exam at least once.

A bag contains 6 blue discs, 10 orange discs and 4 red discs. If a disc is picked at random, what is the probability of getting : a blue, orange or red disc?

What is the critical zvalue that corresponds to a confidence level of 86%

If P(A) = 3/8 What are the odds for A What are the odds against A

A bowl with 2 yellow marbles, 1 blue and 2 red. If you pick one marble from the bowl , list the possible outcomes of the draw.

In a certain high school 65% of students own cell phonoes. 35% own MP3 players. 20% own both cell phones and MP3 players. Identify the probability that a student has either a ceell phone or an MP3 players. Identify the paobaility that a student has only an MP3 player. Identify the probability that a student has neither a cell phone or an MP3 player.

A softball league has ten teams in it. In how many different ways can the team finish first and second?

There are 4 digits on a lock, its each digit is 29 How many combonations are there?

A bag of jelly beans contains 12 cherry, 15 lemon, 17 lime, 13 strawberry, and 18 orange jelly beans. Find the probability that Kelly will get two lemon jelly beans.

A bag contains 6 green marbles, 6 blue marbles, 5 yellow marbles , 13 red marbles, and 10 purple marbles. What is the probability of pulling out a green or a purple?

11 people are racing. What are the odds of being 1st, 2nd or 3rd?

A barrel contains only apples and oranges. There are twice as many apples as oranges. The apples are either red or yellow and 4 times as many red as are yellow. If one piece of fruit is to be drawn at random from the barrel, what is the probability that the piece drawn will be a yellow apple?

Two dice are rolled. It is agreed that if the sum is 7, John will be receiving $10; but for any other sum, John will have to pay out $2. Find the expected amount of money John will receive.

There are 3 entrances and 3 exits to a large parking lot. find the total of number of different ways a driver can enter and exit a parking lot.

In a certain game each of the 5 players recieved a score between 0 and 100 inclusive. If thier average score was 80, what is the greatest possible number of the 5 players who could have recieved a score of 50?

A telemarketer makes six phone calls per hour and is able to make a sale on 30 percent of these contacts. During the next two hours, find the probability of making exactly four sales.

A poll is conducted the day before a state election for senator. There are only two candidates and the poll shows that 53% of the oters surveyed favor the Green candidate, with a margin of 2.5 percentage points. Should the Green candidate plan a victory party? Why or why not?

The average age of 30 soldiers is 25. The average age of first 15 of them is 24 and the last 14 of them is 26 years. What is the age of the 16th soldier?

The average salary for firstyear teachers is $27,989. If the distribution is approximately normal with a standard deviation of $3250, what is the probability that a randomly selected firstyear teacher makes these salaries? a. between $20,000 and $30,000 per year; b. less than $20,000 per year.


Tioga Printers usually has 3 printing or typo error for every 100 pages when printing the first edition of a book. Becky has found 10 printing errors and 4 mathematical errors in the first edition of Ian Stewart`s 287 page The Story of Mathematics. How many printing errors would be expected in this 287 page book?

I put 7 brown beans, 6 white beans, 4 yellow peas and 3 green peas all into a container. What are the chances that I can pick out a green pea 4 times in a row. I will use a pair of tweezers so that I can`t feel the shapes, and yes, I replace the items after each selection.

A sample of 900 homes sold recently in a state gave the mean price of the homes equal to $200,000. The standard deviation of the prices of all the homes in this state is $48,000. Construct a 99% confidence interval for the mean price of all homes in this state. (Any time you round, round to four decimal places.)

A university dean knows the age of students at the school during the 1960s was normally distributed with a mean of 20.2 years and a standard deviation of 4.2 to determine if this demographic variable has substantially changed, a random sample of 36 current students is selected and the age recorded from each of them. For this sample the mean is 23.0. Is there significant difference in age between today students and those enrolled in the 1960? Test with an alpha of .05

Sue is considering loaning 5000 to her brother for a business venture. Her brother promises to pay her back and he`ll give her an extra 10000 if his buisness is an instant success. Sue believes there is only a 15% chance that his business will succeed, and she believes that there is a 10% chance that he will never repay the loan. B) Compute Sue`s expected profit on the loan, and standard deviation C) Should sue expect to profit or lose money from the loan? Is this a risky investment, or is it fairly safe? Justify your answers with the statistics computed.

If the life, in years, of a washing machine is normally distributed with a mean of 20 years and a standard deviation of 1.5 years, what should be the guarantee period if the company wants less than 1% of the machines to fail while under warranty?

In Prof. Smith`s management course the correlation between the students` total score before the final examination and their final examination scores is r=.06. The preexam totals for all students in the class have mean 280 and standard deviation of 30. The final exams scores have mean of 75 and standard deviation of 8. Prof Smith lost Suee`s final exam but knows that her total before the esam was 300. He decides to predict her final exam score from her preexam total.

The mayor of a small town estimates that 35% of the residents in his town favor the construction of a municipal parking lot. If there are 350 people at a town meeting, find the probability that at least 100 favor construction of a parking lot. Based on your answer, is it likely that 100 or more people would favor the parking lot.

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and wakingeven if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed(individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25,27,25,23,25,26, and 25. Using the 5% level of significance, what should we conclude about the theory that 24 hours is the natural cycle? a) Use the steps of the hypothesis testing. b) Sketch the distributions involved.

The median height of the 21 players on a girls` soccer team is 1.7 meters. What is the greatest possible number of girls who are less than 1.7 meters tall?

Mean of $100,000 and a standard deviation of $35,000. What percentage of houses have prices between $90,000 and $130,000 ?

30% of a firm`s orders come from new customers. A simple random sample of 100 orders will be used to estimate the proportion of new customers. Find probability that sample proportion will be between 0.22 and 0.40.

Of the 148 students honored at an academic banquet, 40 won awards for mathamatics and 82 for English. One of the 148 students is chosen at random to be inter viewed for a newspaper article. What is the probability that the student won an award in matematics or English, given that 12 won awards for both?

Consider a binomial experiment with n=20 and p =.70 compute f(0)

Test for high school students with a 3.50 to 4.00 grade point average were normally distributed, with a mean of 38.8 and a standard diviation of 1.9. A student with a 3.5 to 4.00 grade point average who took the standarized tes is randomly selected. The probability of a student scoring less than 36 is?

A reading program is administered to the bottom 5% of the students. If the average score of the students is 122.6, find the cutoff score that will make a student eligible to the program. The standard deviation is 18 and assume that the variable is normally distributed.

In a class of 25 students, the grades were normally distributed with a mean of 78 and a standard deviation of 5. Sketch the normal curve for the distribution. What percentage of the students scored above an 88? How many students scored above an 88?

A manufacturer of automobile batteries claims that the average length of life for its grade "A" battery is 60 months. However the guarantee on this brand is just for 36 months. Suppose the standard deviation of the life length is known to be 10 months, and frequency distribution of the lifelength is known to be bell mound shape.

A pediatrician`s records show that height of a random sample 25 girls at age 12 months to be 29.530 inches with a standard deviation of 1.0953 inches. Construct a 95 percent confidence interval for population variance.

How many ways can you choose 5 players out of 10?

The mean amount of time that a manager spends in annual performance review with an employee is 27.2 minutes, with a standard deviation of 4.9 minutes. What percentage of the annual performance reviews in the department take between 22.3 and 32.1 minutes? Between 17.4 and 37 minutes? Between 12.5 and 41.9 minutes? Explain answer.

With a height of 69 inches, Alexander was the shortest president of a particular club in the past century. The club presidents of the past century have a mean height of 75.4 inches and a standard deviation of 2.7. a. What is the difference between Alexander`s height and the mean? b. How many standard deviations is that [the difference found in part a]?

By the year 2020, in a land far away, the federal government requires car manufacturers to have a minimum of 30 miles per gallon (mpg) average over all the models it makes. Suppose that the GenYota company produces only five models with current mpg ratings of 21, 31, 22, 28, and 18. The manufacturer decides that it can only redesign the last of the models to meet the government requirement. What must the new mpg of this new fifth model be to meet the requirement for the five cars? (Round to the nearest mpg.)

A supplier of CD`s claims that only 1% of disks are defective. In a random sample of 600 disks, it was found that 18 are defective. At 0.05 level of significance, use 1Prop Ztest to test the supplier`s claim that 1% are defective.

A whole sale distributor has found that the amount of a customer`s order is a normal random variable with a mean of $200 and a standard deviation of $50. What is the probability that the total amount in a random sample of 20 orders is greater than $4500?

In France, years of life expectancy are normally distributed with a mean of 81 years and a standard deviation fo seven years. For the French population: a) What is the probability of living 92 years or more? b) What is the probability of living between 78 and 88 years?

At a fair, 37 pumpkins were entered for judging under the normal pumpkin division. If the masses are normally distributed and the average weight is 12.4 kg, with a standard deviation for 2.31 kg. What is the probability that a pumpkin has a mass between 13.5kg and 15kg?

A normal distribution has a mean of 80 and a standard deviation of 14. Determine the value above which 80% of values will occur?

mean height 65.5 inches and standard deviation 3.2 with normal distribution.

for a specific year, american spent an average of $71.12 for books. Assume the variable is normally distributed.If the standard deviation of the amount spent on books is 8.42, find these probabliities for a normaly selected americans. 1. he or she spent more than $60 per year on books. 2. He or she spent less than $ 80 per year on books.

the average amount of rain is 50 inches per year. the standard deviation is 5.5. what is the probability that next year, it will rain at most 55 inches

Heights of young adult U.S. women are approximately normal with mean 64" and standard deviation 2.7". What proportion of all U.S. young adult women are taller than 6 feet?

If the time required for a student complete an aptitude test is distributed as N( x ; 55,10 ) where x is minutes, then what is the probability that more than 3/4 of the 100 students who take the test will complete it, if it is terminated after 1 hour .

standard devition for number of cars in different nations (per 100 population): United States 50; Canada: 45; France 47; Germeny 21; Japan 40; Mexico 10.

A telemarketer with B2B Communication has a 20 percent historical probability of making a sale during a shift where 100 calls were made. Assign a random variable x, where the value of x is equal to the number of sales made during the shift. Describe the probability distribution of x, and calculate the probability of the employee will making exactly 28 sales during a 100  call shift. What is the probability that the employee will make less than 28 sales during the 100 call shift? What is the probability that the employee will make 28 or more calls during the 100 call shift?

The life of a certain battery has a normal distribution with an average of 100 hours and a standard deviation of 4.5 hours. What is the probability that a randomly selected battery lasts from 95 to 105 hours?

how many even 5 digit numbers can be formed from the numbers 1,2,4,7,8, if no digit is repeated in a number?

Suppose that scores on a particular test are normally distributed with a mean of and a standard deviation of . What is the minimum score needed to be in the top of the scores on the test? Carry your intermediate computations to at least four decimal places, and round your answer to at least one decimal place.

If a random variable has a normal distribution, what is the probability that it will take on a value within one standard deviation of the mean, within two standard deviation of the mean?

what are the odds of picking up a 710 spare in bowling?

Standard deviation of a group of 40 students` test scores was calculated as 6.5 points on a 100 point test and the mean of thier distribution of scores was 75.5 points. vind z value of each students` scores

A potato chip company packages its potato chips into 12.0 ounce bags. You find it hard to believe that the bag contains enough potato chips to weigh 12.0 ounces and would like to make an official complaint. Before doing so, you decide to run an experiment so that you can have some confidence that the company’s claim is incorrect. Over the next several months you buy 30 bags of potato chips and weigh the contents of each one. You discover that the mean weight is 11.9 ounces with a standard deviation of 0.4 ounces. You decide that you will only complain if you can be 95% sure that the bags do not contain at least 12.0 ounces of potato chips. You decide to construct a hypothesis test.


A certain airplane has two independent alternators to provide electrical power. The probability that a given alternator will fail on a 1hour flight is .02. What is the probability that (a) both will fail? (b) Neither will fail? (c) One or the other will fail?

Jen scored an 88 on her midterm. Out of the 14 other students in her class, 7 of them scored lower than she did. What was the median of the class midterm scores?

The average salary for firstyear teachers is $27,989. If the distribution is approximately normal with a standard deviation of $3250, what is the probability that a randomly selected firstyear teacher makes these salaries? a. between $20,000 and $30,000 per year; b. less than $20...

What is the critical zvalue that corresponds to a confidence level of 86%?

Suppose the variance = 289. Find the standard deviation.

A RANDOM SAMPLE OF 25 BOOKS HAS A VARINACE OF 81 PAGES. fIND THE 95% CONFIDENCE INTERVAL OF THE TRUE POPULATION VARIANCE

There are 5 packages with a mean weight of 6.7 pounds. Four of the packages have a mean weight of 7.2 pounds. What is the weight of the other package?

a business office in the northern part of the united states is considering the installation of air conditioning. One of the advocates of installing air conditioning insists that the increased efficiency of the office staff will pay for the cost. The annual cost of air conditioning has been compiled, but measuring the increased efficiency of the office employees raises many questions. Outline a method for measuring the increase in efficiency that could be expected as a result of air conditioning the office. The measurement should make possible the computation of the total monetary savings of the air conditioning installation.

A bag contains 5 black, 1 red, and 3 yellow jelly beans; you take 3 at random. How many samples are possible in which the jelly beans are 2 yellow and 1 black.

Jorge got 6 hits in 2 games, and his median number of hits was 2. Create data for the 12 games that could be Jorge`s hits last season

Karl has eight people in his family. he wondered how many hours of TV each of them might have watched in a week if the mean of the eight values were five hours. Write down eight amounts of TVwatching time that have a mean of five hours.

Suppose a candidate running for sheriff claims that she will reduce the average speed of emergency response to less than 30 minutes. (30 minutes is thought to be the average response time with the current sheriff.) There are no past records, so the actual standard deviation of such response times cannot be determined. Thanks to this campaign, she is elected sheriff, and careful records are kept. The response times for the first month are 26, 30, 28, 29, 25, 28, 32, 35, 24, and 23 min. Using the .05 significance level (Check your appendix for section 3—tdistribution chart), did she keep her promise? Go through the five steps of hypothesis testing.

Dr. Stallter has been teaching basic statistics for many years. She knows that 80 percent of the students will complete the assigned problems. She has also determined that among those who do their assignments, 90 percent will pass the course. Among those students who do not do their homework, 60 percent will pass. Mike Fishbaugh took statistics last semester from Dr. Stallter and received a passing grade. What is the probability that he completed the assignments?

Mandy found the range, median, and mode of 5 numbers. The range was 2, the median was 2, and the mode of the numbers was 2. What were the 5 numbers?

90% of buses are green what is the probability that in a sample of 8 buses, at least 7 will be green

kristy has 4 dogs and 2 cats. The mean age of her pets is 3 years. What will their mean age be 10 years from now? twenty years from now?

A telemarketer makes six phone calls per hour and is able to make a sale on 30 percent of these contacts. During the next two hours, find: A) The probability of making exactly four sales. B) The probability of making no sales. C) The probability of making exactly two sales. D) The mean number of sales in the two hour period.

A teacher was comparing results on two sets of test scores for a group of eleven students. The mean score on the second test was seven points higher that that of the first test. The median grade on both tests was the same. Determine two sets of test scores that would produce these results.

in a testing a new rug, researchers found that 5% of all patients using it will have amild side effect. A random sample of 15 patients using the drug is selected. Find the probability that exactly three will have this mild side effect.

A newspaper editor once claimed that more than half American families earned a belowaverage income. Could this claim possibly be correct?

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25.

how to calculate the correct median given that the wrong median?

what is the median of 15 14 12 10 7 7 6 5 9

if you scored 83, 75, and 88 on your first three exams and you want your overall exam average on fours exams to be 80, what must you scored on the fourth exam?

A student measures the length of a room to be 4.64 meters. If the actual length of the room is 5.80 meters, what is the student`s % deviation?

According to the sleep foundation, the average night`s sleep is 6.8 hours (Fortune, March 20, 2006). Assume the standard deviation is .6 and that the probability distribution is normal. a. What is the probability that a randomly selected person sleeps more than 8 hours? b. What is the probability that a randomly selected person sleeps 6 hours or less? c. Doctors suggest getting between 7 and 9 hours of sleep each night. What percentage of the populations gets this much sleep?

what sample size was used in this survey?

Gina has an average of a 66% on her first 7 exams. What grade must she earn on her 8th exam to earn a 70%?

A tire company tested another model of tire and found the tires to be normally distributed with respect to wear. The average (mean) tire wore out at 46,000 miles, and the standard deviation was 24,000. IF 2000 tires were tested, about how many are likely to wear out before 45,000 miles?

6 people are riding in car that has three seats in the front and three seats in the back. If one person refuses to ride in the front and two people refuse to ride in the back, how many possible seating arrangements are there?

1. A normal distribution has a mean of 20 and a standard deviation of 4. a) Find the percentile rank for a data value of 17 ( i.e. find the percentage of data values that are below the data value of 17.

A dailly record was kept of the number of animals each worker stuffed at a toy factory. Each stuffed animal was 40 cents per completely stuffed animal. At the end of the summer, each of the two workers had the same mean number but Bob had a standard deviation of 18 while mike had a standard deviation of 8. which earned more?

A student of the author weighed a simple random sample of steak,s and the results are listed below. The steaks are supposed to be 21 oz. beause they are listed on the mu as weight 20 oz. and the lose an ounce whne cooked. Use the listed weights to find the mean. 17, 19, 21, 18, 20, 18, 19,20, 20, 21

the amount of daily deposits and daily withdrawals are given by independent random variables withnormal distributions.For deposits,the mean is $12000 and standard deviation of 4000.For withdrawals the mean is $10000 and standard deviation is $5000.Find the probablity that on any particular day the with drawal is greater than deposits

A math professor notices that scores from a recent exam are normally distributed with a mean of 69 and a standard deviation of 4. (a) What score do 75% of the students exam scores fall below?

eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25. Using the 5% level of significance, what should we conclude about the theory that 24 hours is the natural cycle? (That is, does the average cycle length under these conditions differ significantly from 24 hours?) (a) Use the steps of hypothesis testing. (b) Sketch the distributions involved. (c) Explain your answer to someone who has never taken a course in statistics.

Racial profiling by the LAPD. Does the Los Angeles Polic Department (LAPD) invoke racial profiling in stops and searches of Los Angeles drivers? This question was addressed in Chance (Spring 2006). Data on stops and searches of both AfricanAmerican and white drivers from January through June 2005 are summarized in the accompanying table. Conduct a test (at alpha = 0.5) to determine whether there is a disparity in the proportions of AfricanAmerican and white drivers who are searched by the LAPD after being stopped. AfricanAmerican Stopped 61,688 Searched 12,016 Hits 5,134 White Stopped 106,892 Searched 5,312 Hits 3,006

331 students went on a field trip. Six buses were filled and 7 students traveled in cars. How many students were in each bus?

Kristy has 4 dogs and 2 cats. The mean age of her pets is 3 years. What will their mean age be 10 years from now.

Given the normal distribution of scores with mean=60 and S.D.=2, what is the proportion of scores do you expect to be greater than 56.5?

Assume that the age of onset of disease X is normally distributed with a mean of 50 years and a standard deviation of 12 years. What is the probability that an individual afflicted with X had developed it before age 35?

A bowl containing 4 red and and 6 black balls is sampled 3 times without replacement. What is the probability of obtaining 3 black balls?

Population mean= 800 and standard deviation= 150; If you were to select a random sample of 500 students how many would you expect to have in your sample who spent $750 or less on clothing?

the average age of lawyers is 40 years, with a standard deviation of 3 years. if a law firm employs 36 lawyers, find the probability that the average age group is lower than 39 years old.

assume a sample of 1000 flies. find the probability that exactly 980 flies are killed.


Suppose that a company knows it has an average of $1450 per claim (standard deviation, $150). What is the probability that the next claim it receives is over $1000?

At work Mr. Bussmann must wear a dress shirt, long pants, and shoes. He has four dress shirts(red, blue, orange, purple), three pairs of pants (green, yellow, tan) and two pair of shoes (white, black) Find out how many different outfit he has for work.

a standard achievement test has a mean of 50 and a standard deviation of 10. (a) Find the probability that a student scores at least 55. (b) Find the percentage of scores that will fall between 47 and 57. (c) If the test is to be administered students, approximately how many will score below 45?

find the variance for 13, 1, 17, 11, 14,

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25. Using the 5% level of significance, what should we conclude about the theory that 24 hours is the natural cycle? (That is, does the average cycle length under these conditions differ significantly from 24 hours?) (a) Use the steps of hypothesis testing. (b) Sketch the distributions involved. (c) Explain your answer to someone who has never taken a course in statistics.

1500 individuals, 700 are women. 240 of the women earn at least $50,000 per year and 300 of the men earn at least $50,000 per year. What is the probability that one randomly selected individual is male conditional on the fact that he earns more than $50,000 per year?

On an auto mechanic aptitued test, the mean score is 270 points and the standard deviation is 35 points a) if a students has a standardized score of 1.9, how many points is that?

36% of voters are democrats. If 2 voters are randomly selected, what are the odds that 2 are democrats?

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight.

The mean on this test is 3.5 with a standard deviation of .5. 1. Sally scores 1.5 on this test. How many standard deviations is Sally from the mean?

The online access computer service industry is growing at an extraordinary rate. Current estimates suggest that only 20% of the home based computers have access to online services. The number is expected to grow rapidly in the next 5 years. Suppose 25 people with homebased computers were randomly and independantly sampled. Find the probabliity that fewer than 10 currently have access to online services

The online access computer service industry is growing at an extraordinary rate. Current estimates suggest that only 20% of the home based computers have access to online services. The number is expected to grow rapidly in the next 5 years. Suppose 25 people with homebased computers were randomly and independent sampled. Find the probability that fewer than 10 currently have access to online services

the mean inside diameter of a sample of 200 washers produced by a machine is 0.0502 inches and the standard deviation is 0.005 inches. the purpose for which these washers are intended allows a maximum tolerance in the diameter is 0.496 to 0.508 inches, otherwise the washers produced by the machine, assuming the diameters are normally distributed

A professor at a local university noted that the grades of her students were normally distributed with a mean of 78 and a standard deviation of 10. a. The professor has informed us that 16.6 percent of her students received grades of A. What is the minimum score needed to receive a grade of A?

3 cub scouts sold boxes of popcorn. the mean number of boxes sold was 4. What are 2 different data sets of numbers that could represent what each boy sold?

what is the median of 37, 21, 14, 18, 34, 17, 21, 9

you roll a die 15 times and count the number of times you get a 3 or a 4. What is the probability that you roll a 3 or 4 a total of 9 times?

An automobile manufacturer has three factories, A, B, C. They produce 50, 30, and 20%, respectively, of a specific model of car. 30% of the cards produced in the factory A are white, 40% of those produced in factory B are white, and 25% produced in factory C are white. If an automobile produced by the company is selected at random, find the probability that it is white.

Number of children Probability 0 .050 1 .125 2 .600 3 .150 4 .050 5 .025 If a couple is selected at random, what is the probability that the couple will have either 2 or 3 children?

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25.

The amount of soda a dispensing machine pours into a 12 ounce can of soda follows a normal distribution with a mean of 12.24 ounces and a standard deviation of 0.16 ounces. The cans only hold 12.40 ounces of soda. Every can that has more than 12.40 ounces of soda poured into it causes a spill and the can needs to go through a special cleaning process before it can be sold. What is the probability a randomly selected can will need to go through this process?

What is the critical zvalue that corresponds to a confidence level of 88%?

Suppose the scores of a Calculus test follows a normal distribution with a mean of 75 and a standard deviation of 8. Suppose the top 15% students will get an A. What is the cutoff score for A?

what is the probablity of rolling 5 heads with five coin tosses in a row

what is the probablity of rolling 5 heads in a row with five coin tosses

Mean of 440 seconds and a standard deviation of 60 seconds. Find the probability that a randomly selected boy in secondary school can run the mile in less than 302 seconds.

The leading brand of dishwashers has a 20% market share. A sample of 15 dishwashers customers were taken. What is the expected value and the variance for the number of customers who use the leading brand?

the mean yield a given year for sugar beets is 22 tons/acre and the standard deviation 3.8. For a sample of 280 fields, find the approximate number with a yield between 18.2 and 25.8. assume a normal distribution


according to a census the median age of the 281421906 people surveyed is 35.3 years. About how many people are older than 35.3 years?

the weekly amount of money spent on cleaning,maintenance, and repairs at a large restaurant was observed over a long period of time to be approximately normally distributed with u= $615 and the standard deviation o= $42 a) if $646 is budgeted for the next week, what is the probability the actual costs will exceed the budget amount

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking

What is the critical zvalue that corresponds to a confidence level of 88%

IN A CLASS,THE MEAN SCORE IS 60.STANDARD DEVIATION =4.2,JOHN`S SCORE=2 STANDARD DEVIATION AWAY FROM THE MEAN.WHAT IS JOHN`S SCORE?

what is the critical zvalue that corresponds to a confidence level of 88

A simple random sample of 40 salaries of NCAA football coaches has a mean of $415,953 and a standard deviation of $463,364. Find the best point estimate of the mean salary of all NCAA football coaches.

The average gas mileage of a certain model car is 28 miles per gallon If the gas mileages are normally distributed with a standard deviation of 1.7 find the probability that a car has a gas mileage?

Some colleges have pushed back the starting time of morning classes because students were not getting enough sleep. A random sample of 20 college students had an average of 6.4 hours of sleep and somehow we know that standard deviation of population 1.90 hours. Assuming the population is normally distributed, compute and interpret a 95% confidence interval for the true mean amount of sleep that college students get per night.

an aerobic class is being offered once a week for 6 weeks. the registration fee is $15 and the cost for each class attended is $10. write a function rule to describe the total cost of the class. Find a reasonable domain and range for the function.

Antonio measures the alcohol content of whiskey for his Chemistry 101 lab. He actually measures the mass of 5.8 milliliters of whiskey  a chemical calculation then finds the percent alcohol from the mass. The standard deviation of students` measurements of mass is σ = 10.6 milligrams (mg). Antonio repeats the measurement 8 times and records the mean x of his 8 measuremen (b) How many times must Antonio repeat the measurement to reduce the standard deviation of x to 3.75 mg? 2Your answer is incorrect.

Antonio measures the alcohol content of whiskey for his Chemistry 101 lab. He actually measures the mass of 5.8 milliliters of whiskey  a chemical calculation then finds the percent alcohol from the mass. The standard deviation of students\` measurements of mass is σ = 10.6 milligrams (mg). Antonio repeats the measurement 8 times and records the mean x of his 8 measuremen (b) How many times must Antonio repeat the measurement to reduce the standard deviation of x to 3.75 mg? 2Your answer is incorrect.

Micheal is 190 cm tall. In his high school, heights are normally distributed with a mean of 165 cm and a standard deviation of 20 cm. What is the probability that Micheal`s best friend is shorter than he is?

Micheal is 190 cm tall. In his high school, heights are normally distributed with a mean of 165 cm and a standard deviation of 20 cm. What is the probability that Micheal\`s best friend is shorter than he is?

Micheal is 190 cm tall. In his high school, heights are normally distributed with a mean of 165 cm and a standard deviation of 20 cm. What is the probability that Micheal\\\`s best friend is shorter than he is?

Twenty students randomly assigned to an experimental group receive an instructional program; 30 in a control group do not. After 6 months, both groups are tested on their knowledge. The experimental group has a mean of 38 on the test (with an estimated population standard deviation of 3); the control group has a mean of 35 (with an estimated population standard deviation of 5). Using the .05 level, what should the experimenter conclude? (a) Use the steps of hypothesis testing, (b) sketch the distributions involved, and (c) explain your answer to someone who is familiar with the t test for a single sample, but not with the t test for independent means.

A student receives the following grades, with an A worth 4 points, a B worth 3 points, a C worth 2 points, and a D worth 1 point. What is the students weighted mean grade point score?

a cyclist travels 60 km at a constant speed of 20 km/h and returns, with the wind behind him, averaging 30 km/h.

the average blood pressure of a group of men is 125 mm and the sd is 15 mm. a histogram of the blood pressures is roughly bell shaed. About 25 % of the men have blood pressure less than __?

75 employees from a large company were randomly surveyed in regards to the length of time they have been working for the company. The sample revealed a mean of 8.2 years and a standard deviation of 2.3 years. what is the value of the point estimate of the population mean?

what is the average age of three sisters in the terms of the age a of the firstborn (in years), if the second was born 3 years after the first and the third was born 2 years after the second?

What is the missing number? ___, 82, 83, 68, 84, 76,72,77 Average: 75

A social networking site claims its membership is about 50%50% between males and females. if 400 members are chosen at random, what is the probability that the proportion of females in the sample would be great than 52%?

The number of eggs a female house fly lays during her lifetime is normally distributed, with a mean of 800 eggs and a standard deviation of 100 eggs. Random sample of size 15 are drawn from this population and the mean of each sample is determined. Use the Central Limit Theorem to find the mean and standard error of the mean of the indicated sampling distribution.

how many different combinations can you make 41 cents out of quarters, dimes, nickels and pennies?

susan` sbowling scores have a range of 20 points. Dan`s scores are each 10 points greater than Susan`s scores. Will Dan`s range be greater than, less than, or equal to Susan`s range?.

a barrel contains only apples and oranges. there are twice as many apples as oranges. the apples are either red or yellow, and 4 times as many apples are red as are yellow. if one piece of fruit is to be drawn at random from the barrel, what is the probability that the piece drawn will be a yellow apple?

32 people using 7 cars. what is the probabilty of the people staying out 60% of the time in 30 days

A telemarketer makes six phone calls per hour and is able to make a sale on 30% of these contacts. During the next two hours

Five men and three women apply to work on a special project that requires seven people. If the project team members are selected at random what is the probability that no women will be selected?

a normal population has a mean of 75 and a standard deviation of 5. Between 74 and 76 less than 74 between 76 and 77 greater than 77

A scale measuring confidence in the media was administered to a sample. Is there a statistically significant difference between Democrats and Republicans on the scale? Higher scores on the scale indicate greater confidence. use the five step model and write a sentence or two interpreting your results.

Jeannie is an experienced business traveler, often traveling back and forth from San Francisco to the East Coast several times per month. To catch her flights from San Francisco she leaves her office one hour before her flight leaves. Her travel time from her office to the departing gate at the San Francisco airport, including the time to park and go through security screening, is normally distributed with a mean of 46 minutes and a standard deviation of 5 minutes. What is the probability that Jeannie will miss her flight because her total time for catching her plane exceeds one hour? Round your final answer to 4 decimal places.

A recent survey of local cell phone retailers showed that of all cell phones sold last month, 64 % had a camera, 28% had a mp3 player, and 22 % had both. what is the probability that a cell phone sold last month had a camera or a mp3 player ?

How many different ways can five managers be seated a round table?

in attempting to control a porcess, why is it important to systematically check both the center and the variability of measurements of the process?

Between what values is it expected that 95% of chipmunks are in, with a sample size of 49, mean of 8.2 oz and a standard deviation of 2.1 oz.

A batch of 100 Barbie dolls contains four (4) defective dolls. What is the probability that a sample of three (3) dolls from this batch will contain: a. no defective dolls? b. all defective dolls? c. at least one defective doll? d. at least one nondefective doll?

3) A recent poll of 400 Florida voters showed the following results: SUPPORT stronger growth management laws = 45%, OPPOSE stronger growth management laws = 40%, and all others UNDECIDED. Based on these results can the governor conclude that more Florida voters SUPPORT – rather than OPPOSE – stronger growth management laws?

If a student has a standardized score of 1.9, how many points is thatWITH THE MEAN =264 AND ST=40

About 11% of the population is allergic to pollen. If two people are randomly selected, what is the probability both are allergic to pollen? What is the probability at least one is allergic to pollen?

from long ago experience, it is known that the time it takes to do an oil change and lubrication job on a vehicle has a normal distribution with mean= 17.8 and standard deviation= 5.2. an auto service shop will give a free lube job to any customer who must wait beyond the guaranteeed time to complete the work. if the shop does not want to give more than 1% of its customers a free lube job, how long should the guarantee be?

from long ago experience, it is known that the time it takes to do an oil change and lubrication job on a vehicle has a normal distribution with mean= 17.8 and standard deviation= 5.2. an auto service shop will give a free lube job to any customer who must wait beyond the guaranteed time to complete the work. if the shop does not want to give more than 1% of its customers a free lube job, how long should the guarantee be?

The demand for ultralite pencils has been fairly stable over last 6 years. On the average, they have sold 457,000 pencils each year. Furthermore, 90% of the time sales have been between 454,000 and 460,000 pencils. It is expected that the sales follow a normal distribution with a mean of 457,000 pencils. Estimate the standard deviation of this distribution.

mean of 80 and a standard deviation of 14.0 compute the probability of a value between 75 and 90

The number of litres X that a a lling machine in a water bottling plant deposits in a normal two litre bottle follows a normal distribution N(; 2), where = :01 (litres) and is the setting on the machine. (a). If = 2:00, what is the probability a bottle has less than 2 litres of water in it? (b). What should be set to make the probability a bottle has less than 2 litres be less than :01?

a statistics professor gies a test and finds that the scores are normally distributed with a mean of 25 and standard deviation of 5 she plans to crese the scores by adding 50 points to each grade what is the new mean? What is the new standard deviation?

an almanac reports the average person uses 118 gallons of water daily. If the standard deviation is 24 gallons, find the probability that the mean of a randomly selected sample of 15 people will be between 116 and 120 gallons. Assume the variable is normally distributed. Round your answe to two decimals

There are 5000 sold of those 200 are defective, what is the probablity that 100 randomly selected are good

if u have 4 reds, 3 green, and 2 white. what is the proportion if u take 1 red out?

a theatre presented five performances a total of 1860 people attended during the week what was the avaragesize of the audience each night

a theatre presented five performances a total of 1860 people attended during the week what was the avarage size of the audience each night

Suppose the standard deviation is 12.4. What is the variance?

Business Week reports that its subscribers who plan to purchase a new vehicle within the next 12 months plan to spend a mean of $27,100 on the new vehicle. Assume that the new vehicle price for the population of Business Week subscribers has a mean of $27,100 and a standard deviation of $5,200. What is the probability that the sample mean new vehicle price for a sample of 30 subscribers is within $1000 of the population mean?

Each of these bags contains 2 apples. One bag contains 2 green apples, another 2 red apples and a 3rd one, one green and one red apple. All 3 bags are mislabeled. You may look at only 1 apple from any one of the bags. Which bag should you select from to be sure you can determine the content of all three bags?

Chances of winning the Power Ball


For a normally distributed population, approximately 68 percent of the population lies within 1 standard deciation of teh mean and approximately 95 percent of the population lies within 2 standard deciations of the mean. In a certain environmental study, the weights of 10,000 fish are normally distributed with a mean of 12.5 ounces and a standard deciation of 4.2 ounces. Approximately what percent of the 10,000 fish have weights between 16.7 and 20.9 ounces?


suppose 70% of crimes occur at night, that 8% that occur at night are violent, and that only 2% of crimes during the day are violent

Adam tried to compute the average of his 7 test scores. He mistakenly divided the correct sum of all of his test scores by 6, which yielded 84. What is Adam’s correct average test score?

The mean of a normal distribution is 100 and the standard deviation is 15. Find the value of separating the top 85% from the others.

The coding supervisor is ordering office supplies for second quarter of the fiscal year. The budgeted amount for supplies for the year is $5,000 and to date $3,500 has been expended. If the allocated amount is $1,250 per quarter, what is the variance to date for this line item?

A student takes a 20question, true/false exam and on each question.Find the probability of passing if the lowest passing grade is 15 out of 20 .Would you consider this event likely to occur? Explain you answer.

The diameter of a wooden dowel produced by a new machine are normally distributed with a mean of 0.55 inches and a standard deviation of 0.01 inches. What percent of the dowels have a diameter of less than 0.56

Suppose the standard deviation is 12.4.

2500 employess avg 15.5 years standard devitation 6.1 years how many with over 18 yrs



Step by step instructions on how to solve A certain airplane has two independent alternators to provide electrical power. The probability that a given alternator will fail on a 1hour flight is .02. What is the probability that (a) both will fail?

A standardized test was given. Group 1: mean score is 300, and a standard deivation of 40. Group 2: mean score of 305 and standard deviation of 20? what is the difference?

Assume that the length of time, x, between charges of a pocket calculator is normally distributed with a mean of 100 hours and a standard deviation of 15 hours. Find the probability that the calculator will last between 80 and 120 hours between charges

Assume that the length of time, x, between charges of a pocket calculator is normally distributed with a mean of 100 hours and a standard deviation of 15 hours. Find the probability that the calculator will last between 80 and 120 hours between charges.

Ifon a $5 bet Marty`s ecpected value is $0.40, what is Marty`s ecpectec vlaue on a $25 bet, and hoe much can Marty ecpect to gain or lose if he places a $10 bet?

Ifon a $5 bet Marty\`s ecpected value is $0.40, what is Marty\`s ecpectec vlaue on a $25 bet, and hoe much can Marty ecpect to gain or lose if he places a $10 bet?

For a student to graduate, a high school requires that each student demonstrate competience in mathemantics by scoring 70 or above on a mathematics achievement test. The scores of those students taking th test are normally distributed with a mean of 74 and a standard deviation of 4.8. Find the score seperating the top 10% from the others.

he has 50$ to spend. the movie costs 8$ per person. what is the range?

jim recieved a grade of 60 on a test. the mean was 85, and the standard deviation was 10. Assuming grades are normally distributed, what percentage of the class scored at his level or better?

at a raffle 10,000 tickets are sold at 5 dollars each for 3 prizes valued at 4800 dollars,1200 dollars,400 dollars.what is the expected value of one ticket

X mean and S deviation of asset 100 observation were worked out as 40 and 5 respectively by a computer who by mistake took the value 50 in place of 40 for one observation recalculate the correct mean and variance

30% of a firm`s orders come from new customers. A simple random sample of 100 orders will be used to estimate the proportion of new customers. Find probability that sample proportion will be between 0.22 and 0...

Six students, three boys and three girls line up in random order. What is the probability that the boys and girls alternate?

Suppose the standard deviation is 12.4. What is the variance

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually)b in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights no and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycle at the end of the study was as follows: 25, 27, 25, 23, 24, 25, 26, and 25. Using the 5% level of significance, what should we conclude about the theory that 24 hours is the natural cycle? (That is, does the average cycle length under these conditions differ significantly from the 24 hours?) (a) Use the steps of hypothesis testing. (b) Sketch the distributions involved. (c) Explain your answer to someone who has never taken a course in statistics.

THE DISTRIBUTION OFSCORES ON A HISTORY TEXT IS CLOSE TO NORMAL. THE SCORES ARE ADJUSTED SO THAT THE MEAN SCORE IS 75 AND THE STANDARD DEVIATION IS 5. HOW HIGH MUST A STUDENT SCORE TO FALL IN THE TOP 25%.

1n 1995, the life expectancy of males in a certain country was 71.3 years. In 2001 it was 75.1 years. Let E represent the life expectancy in year and let t represent the number of years since 1995. E(t)=_t+_ and E(10)=__ I don`t know the right data, if it is right in front of me.

weight of rat assumed to be normally distributed with mean weight of 200g and variance of 10g. find rats having weight less than 180g and rats having weight between 100 and 200g

The lifetime for light bulbs has a mean of 4000 hours and a standard deviation of 200 hours. 1) What proportion of the light bulbs will last beyond 4200 hours? 2) What lifetime should the company claim for these light bulbs in order that only 2% of them burn out before the claimed lifetime?

The following frequency distribution was for number of votes for mayor in leavenworth in different precincts Votes 099, 100199, 200299, 300399, 400499 number of precincts 3,10, 25, 15, 22

a 1$ bet says las vegas will pay 5$ if you roll a 7 with two standard dice A) if you play twelve times what is the probability that you`ll win twice B) If you play the game what is the probability that your first win will be the fifth roll C) Before the fifth roll D) if you play 120 times what is the probability you`ll break even? E) if you play twelve times what is the probabilty you`ll win three or more times?

a 1$ bet says las vegas will pay 5$ if you roll a 7 with two standard dice A) if you play twelve times what is the probability that you\`ll win twice B) If you play the game what is the probability that your first win will be the fifth roll C) Before the fifth roll D) if you play 120 times what is the probability you\`ll break even? E) if you play twelve times what is the probabilty you\`ll win three or more times?

a population has a mean of 300 and a standard deviation of 18. a sample of 144 observations will be taken. the probability that the sample mean will be between 297 to 303 is

a service contract on a new university computer system provides 24 free repair calls from a technician. suppose the technician is required on the average of three times a month. What is the pdf for x, the time for a repair call? What is the average time it takes for the service contract to be fulfilled?

find the average time to clean the class rooms on the campus; the duties are emptying trash, wipe desks, vacuum, clean boards, and straighten desks

1. In Prof. Smith’s math course the correlation between the students’ total scores prior to the final examination and their final examination scores is r=0.7. The preexam totals for all students in the course have mean 280 and standard deviation 30. The final exam scores have mean 75 and standard deviation 8. Prof. Smith has lost Julie’s final exam but knows that her total before the exam was 300. He decides to predict her finalexam score from her preexam total. (a). Based on the question above, what is the response variable (y) in the regression model? What is the explanatory variable (x)? Variable response (y) is Explanatory variable (x) is

Suppose the standard deviation is 12.4 What is the variance?

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25. Using the 5% level of significance, what should we conclude about the theory that 24 hours is the natural cycle? (That is, does the average cycle length under these conditions differ significantly from 24 hours?) (a) Use the steps of hypothesis testing. (b) Sketch the distributions involved. (c) Explain your answer to someone who has never taken a course in statistics.

there are 100 student divid equally into 4 class; 54 girl and 46 boys; what is the probabilty that a class will have 15 girls

jim received a grade of 60 on a test. the mean was 85 and the standard deviation was 10. Assuming the grades are normally distributed,what percentage of the class scored at his level or better

Four red and seven black beans are placed into a bag. If one of the beans is selected at random, determine the odds in favor of the bean being black

40% of adults drink coffee but not tea, while 25% drink both coffee and tea. What is the probability that a randomly selected adult does not drink coffee?


A 420 pound man breaks a chair at a restaurant due to his weight. The manufacturer of the chair states that the chair can support a 450 pound man with a standard deviation of 8. The restaurant argues that the average man weighs 185 pounds with a standard deviation of 31 pounds. The man sues for $1 million dollars for pain and suffering but only suffered minor bruises. Who has the stronger case, the man or the restaurant?

find the iq score separating the top 35% from the others


Find the standard deviation for this data set, correct to the nearest tenth. 45 39 26 52 34 30

Use a table of areas for the standard normal curve to find the required zscore. Find the zscore for having area 0.09 to its right under the standard normal curve, that is, find z0.09

Identify the domain and range of the relation: (5,0),(6,0),(7,6),(8,8),(8,10)

how to resolve an standard deviation word problem?

THE PROBAABILITY OF WINNING A VERTAIN LOTTERY IS 1/51, 949. FOR PEOPLE WHO PLAY 560 TIMES, FIND THE STANDARD DEVIATION FOR THE RANDOM VARIABLE x, THE NUMBER OF WINS.

i have quiz grades of 82,82,89,92. what do i need on the next quiz for an average of 88

1000 light bulbs with amean life of 120 days are installed in anew factory, their length of life is normally distributed with standard deviation of 20 days. If it is decided to replace all the bulbs together, what intervals should be allowed between replacements if not more than 10% should expire before replacement?

find the probability that a student will score between 82 and 88 on a test

the neck size of men is normally distributed, with a mean of 15.5 inches for a shirt with a 0.5 inch standard deviation, and a new line of 1,000 shirts will be introduced. How many shirts would have a neck size of 14?

A college only accepts top 10% of students. The average score is 1148.2 and the standard deviation is 121.6. What is the lowest score you can make and still get acepted?

suppose the average amount of cereal in a box is 375 grams with a standard deviation of 14 grams. A simple ransom sample of 49 cereal boxes is selected. . what is the probability the sample mean will be less than 372 grams?

Test the claim that the mean life span of cell phones is different from 5 years. What is the hypotheses

How many ways can you select 3 member group out of 15 people?

The scores of a test have a mean of 100 and a standard deviation of 15. if a personal manager wishes to select from the top 75% of applicants who take the test, find the cutoff score. Assume the variable is normally distributed.

Nutrition experts at a summer camp claims that one`s daily diet contain a minimum of .20 grams of fiber. A unbiased third party want to test the validity of that ascertain. a sample of 400 provided a sample proportion /p = .175. What is the pvalue?

the average of 7 and another number 10. the other number is

The amount of time required to assemble a component on a factory assembly line is normally distributed with a mean of 3.1 minutes nd a standard deviation of 0.6 minutes. Find the percentage of employees taht will take between 2.0 minutes and 2.5 minutes to assemble the component.

1. Professor Kline has 125 students in his Western Civilization Class. At the end of the semester, the average final grade was µ = 68.85 and a standard deviation σ = 7.25. How many students received a final score: a. better than 90? b. between 70 and 85? c. less than 60.50? d. between 60 and 70?

9. A data set consists of 72 test scores. Over a long period it has been found that the mean and standard deviation for these scores are known and that the scores are normally distributed. How many scores within this data set should lie within one standard deviation of the mean? Round your answer to the nearest whole number.

If the standard deviation is 16.9% and the average is 73.2%, what grade would the student receive if she got an 80%?


Test A has mean of 100 and a standard deviation of 18; Test B has mean of 100 and a standard deviation of 14.

Compute the population mean margin of error for a 95% confidence interval when sigma is 4 and the sample size is 36.

1. The mean amount of time required by an appliance repairman to fix a washing machine is 48 minutes with a standard deviation of 6 minutes. At least what percent of the machines should take between 30 and 66 minutes to repair?

The life expectansy in the United States is 75 with a standard deviation of 7 years. A random sample of 49 individuals is selected. What is the probability that the sample mean will be between 73 and 74 years

Melody bought four boxes of Christmas ornaments. Eaach box contained 12 ornaments. There was an average of 2 broken ornaments per box. 3 of the boxes had 1 broken ornament each. How many ornaments were broken in the other box?

An insurance Company classifies drivers as low risk, medium risk, and high risk. of those insured, 60% are low risk, 30% are medium risk and 10% are high risk. after a study the company finds that during a 1year period, 1% of the lowrisks drivers had an accident, 5% of the medium drivers had an accident, and 9% of high risk drivers had an accident. if a driver is selected at random, fin the probility that the driver will have had an accident during the year

A normal distribution has a mean of 20 and a standard deviation of 5. Ninetyfive percent of the scores fall between

In 1991, the life expectancy of males in a certain country was 72.7 years. In 1995, it was 76.2 years. Let E represent the life expectancy in year t and let t represent the number of years since 1991. The linear function E(t) that fits the data is?


In a recent survey, 10 percent of the participants rated Pepsi as being "concerned with my health." Pepsi`s response included a new "smart spot" symbol on its products that meet certain nutrition criteria, to help consumers who seek more healthful eating options. At alpha = 0.05, would a followup survey showing that 18 of 100 persons now rate Pepsi as being "concerned with my health" prove that the percentage has increased?

According to fans the mean score of all NBA games during the last season was less than 100 points per game. Test the claim that the mean score was at least 100 points per game

For a normally distributed population, approximately 68 percent of the population lies within 1 standard deviation of the mean and approximately 95 percent of the population lie within 2 standard deviations of the mean. In a certain environmental study, the weights of 10,000 fish are normally distributed with a mean of 12.5 ounces and a standard deviation of 4.2 ounces. Approximately what percent of the 10,000 fish have weights between 16.7 and 20.9 ounces?

a box contains 2 blue pins and 3 red pins, the color of a pin that is randomly chosen is recorded and the pin is returned to the box, given that this process is repeated 4 tomes and X is the number of times a blue pin is chosen, find the mean value and the standard deviation of X

obtain a list of patients discharged from all MMH facilities. Divide the patients according to length of hospital stay (2 days or less, 37 days, 814 days, more than 14 days). Draw simple random samples from each group.

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25. Using the 5% level of significance, what should we conclude about the theory that 24 hours is the natural cycle? (That is, does the average cycle length under these conditions differ significantly from 24 hours?) (a) Use the steps of hypothesis testing. (b) Sketch the distributions involved. (c) Explain your answer to someone who has never taken a course in statistics.

The mean mileage for a certain Minivan is 19.5 mpg with a standard deviation of 1.8 mpg a. Assuming we know nothing about the shape of the data set, at least what percentage of time will the recorded mileage will be between 16.8 and 22.2 mpg? b. Assuming we can verify that the data set is approximately normally distributed, what percentage of time will the recorded mileage be greater 15.9 mpg? c. Assuming we can verify that the data set is approximately normally distributed, 68% of the mileages will be within what range?

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25. Using the 5% level of significance, what should we conclude about the theory that 24 hours is the natural cycle? (That is, does the average cycle length under these conditions differ significantly from 24 hours?) (a) Use the steps of hypothesis testing. (b) Sketch the distributions involved. (c) Explain your answer to someone who has never taken a course in statistics.

What is the probability of rolling a pair of dice and obtaining a total score of 10 or more


what is the probability of getting a blackjack on the first two cards randomly drawn from a standard deck of 52

a business magazine mailed a questionnaire to the human resource directors of all the fortune 500 comapnies, and recieved responses from 23% of them. 80% of all the reported that they did not find that such surveys intruded significantly on thier workday.

You roll a number cube numbered from 1 to 6 p(an odd number) put in a fraction in simplest form

your school reduces all endofschool scores on a particular thirdgrade math test into zscores which are placed into a districtwide distribution of zscores. Last year, your entering fourth grader ranged between 1 and +2 standard deviations, and this year`s entering fourth graders range between 2 and +3. What do these numbers tell you about the group entering your class?

what is the sample mean for extrinsic value by gender? 5.5 M 3.6 M 6.7 M 5.6 M 5.5 M 4.4 M 6.5 M 6.9 M 4.6 M 6.8 M 5.5 M 3.8 M 6.8 M 4.6 M 6.5 M 6.1 F 3.9 F 6.2 F 5.5 F 4.4 F 4.7 F 6.2 F 4.7 F 5.5 F 4.8 F


300 beans twice as many white than black how many black are there

In a normal distribution, if the mean is 80 and the standard deviation is 10, what percentile corresponds to 1 standard deviation below the mean

On a multiplechoice test, a student is given five possible answers for each question. The student receives 1 point for a correct answer and loses ¼ point for an incorrect answer. If the student has no idea of the correct answer for a particular question and merely guesses, what is the student’s expected gain or loss on the question?

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time.They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25. Using the 5% level of significance, what should we conclude about the theory that 24 hours is the natural cycle? (That is, does the average cycle length under these conditions differ significantly from 24 hours?) (a) Use the steps of hypothesis testing. (b) Sketch the distributions involved. (c) Explain your answer to someone who has never taken a course in statistics.

A researcher is interested in the effects of humidity on the eating behavior of rats. A group of 25 rats is housed in a controlled environment and the researcher measures the amount of food consumed by each rat with the humidity set at 20% and again with the humidity set at 80%.

Suppose the average score on the GMAT is 500 and the standard deviation is 100 points. You would expcet approximately 95% of all GMAT scores to be between?

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24hour cycle of sleeping and waking—even


about 6% of the frankfurters are overstuffed and thus defective. What are the probabilities of 25 or fewer are overstuffed for a sample of 500 frankenfurters?