Friday

July 1, 2016
Number of results: 9,633

**Stor 155**

Use the definition of the mean to show the sum of the deviation of the observations from their mean is always zero. This is one reason why variance and standard deviation use squared deviations.
*August 30, 2012 by ami*

**statistics**

A sample of 12 measurements has a mean of 34 and a standard deviation of 4.5. Suppose that the sample is enlarged to 14 measurements, by including two additional measurements having a common value of 34 each. A. Find the mean of the sample of 14 measurements. Mean = B. Find ...
*May 2, 2011 by Anonymous*

**Business Statistics**

1. Suppose that the mean of the annual return for common stocks from 1950 to 2012 was 9.4%, and the standard deviation of the annual return was 17.5%. Suppose also that during the same 62-year time span, the mean of the annual return for long-term government bonds was 4.6%, ...
*March 6, 2013 by Michelle*

**STATISTICS**

Standard error: Is always the standard deviation divided by the square root of n. Is a measure of the variability of a sample statistic. Increases with bigger sample sizes. All of the above.
*August 6, 2013 by Susie*

**statistics**

Scores on a national writing exam are approximately normally distributed, with a mean of 490 and a standard deviation of 20. Consider random samples of size 25 from the population of test takers. describe the sampling distribution of a sample mean. shape mean= standard ...
*October 17, 2014 by ivan*

**SMU**

A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with a standard deviation of $3.02. For the October 26 evening showing of the same movie, for a sample of 25 purchases the mean was $5.12 with a standard ...
*December 19, 2011 by carl *

**statistics**

using the numbers only 0 through 10 only whole numbers with repeats allowed pick four numbers that would have the smallest standard deviation I said four zeros pick four numbers that would have the largest standard deviation I said 0 0 0 10 is there more than one correct ...
*July 28, 2009 by statistics*

**statistics**

hi, how would i calculate the standard deviation of the following sampling distribution of means. apparently this is the longhanded way of calculating standard error. *a population of scores contains exactly 5 scores : 2, 3, 6, 8, 11 (2, 2) ... 2 (2, 3) ... 2.5 (2, 6) ... 4 (...
*November 21, 2010 by ash*

**statistics**

The most common intelligence quotient (IQ) scale is normally distributed with mean 100 and standard deviation 15. What score would put a child 3 standard deviations above the mean
*September 3, 2012 by Gee*

**statistics**

The most common intelligence quotient (IQ) scale is normally distributed with mean 100 and standard deviation 15. What score would put a child 3 standard deviations above the mean
*September 3, 2012 by Gee*

**Stats**

A large population has a mean of 200 and a standard deviation of 40. Which one of the following best describes the percentage of measurements that fall in an interval that is within two standard deviations of the mean?
*September 14, 2012 by Natalie *

**statistics**

IQ scores distribution of IQ scores is not normally distributed standard with a mean of 100 and a standard deviation of 15, which is represented by a bell-shaped graphical. What is the area under the curve? What is the median? What is the mode?
*April 25, 2015 by norma*

**statistics**

IQ scores distribution of IQ scores is normally distributed standard with a mean of 100 and a standard deviation of 15, which is represented by a bell-shaped graphical. What is the area under the curve? What is the median? What is the mode?
*April 25, 2015 by norma*

**STATISTICS**

IQ scores distribution of IQ scores is normally distributed standard with a mean of 100 and a standard deviation of 15, which is represented by a bell-shaped graphical. What is the area under the curve? What is the median? What is the mode?
*April 25, 2015 by norma*

**statistics**

ok i was given a set of data asked to create a graph of my choice to represent the data then i'm asked Does the sahpe of hte distribution allow the use of the mean and the standard deviation to describe it? ok how does the mean and the standard deviation effect the shape of ...
*July 23, 2009 by statistics*

**statistic**

The mean salary per day of all the 5000 employees who work in a company is 150 Rs. and the standard deviation is 15 Rs. Let be x bar is the mean salary per day for a random sample of certain employees selected from this company. Find the mean and standard deviation for sample ...
*September 1, 2011 by sandhya*

**Math-confused...plz help**

I. Use Chebyshev’s theorem to find what percent of the values will fall between 183 and 227 for a data set with a mean of 205 and standard deviation of 11. II. Use the Empirical Rule to find what two values 99.7% of the data will fall between for a data set with a mean of 297 ...
*October 16, 2011 by Jennifer*

**Math**

Susan owns a chocolate store. She sells her chocolate by the gram and needs to compare the weights of two chocolate batches. She randomly selects 100 pieces from each batch. The distrubition of both samples are normal. Batch 1 - (Mean Weight) 56 grams Standard Deviation - 6 ...
*March 30, 2013 by Caroline*

**statistics**

Please read and use the following information to answer questions 11, 12, and 13: Big packages of M&M Plain Candies have a mean weight of 16 ounces with a standard deviation of .15 ounces. A chocolate loving researcher decides to a random sample of 20 big bags of M&M Plain ...
*October 8, 2014 by mike*

**prob. & stat**

In a random sample of 63 women at a company, the mean salary is $48,902 with a standard deviation of $5270. In a random sample of 50 men at the company, the mean salary is $53,454 with a standard deviation of $4677. Construct a 95% confidence interval for the difference ...
*May 9, 2015 by sweet12*

**prob & stat**

In a random sample of 63 women at a company, the mean salary is $48,902 with a standard deviation of $5270. In a random sample of 50 men at the company, the mean salary is $53,454 with a standard deviation of $4677. Construct a 95% confidence interval for the difference ...
*May 10, 2015 by sweet12*

**statistics**

A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with a standard deviation of $3.02. For the October 26 evening showing of the same movie, for a sample of 25 purchases the mean was $5.12 with a standard ...
*March 1, 2010 by Jennifer*

**Math-Statistics**

I. Use Chebyshev’s theorem to find what percent of the values will fall between 156 and 276 for a data set with a mean of 216 and standard deviation of 12. II. Use the Empirical Rule to find what two values 68% of the data will fall between for a data set with a mean of 219 ...
*January 20, 2011 by Tameka*

**Math(Please Help Assignment Due Tomorrow)**

From the length(in seconds) of 80 randomly chosen U2 songs, the mean determined was 289.6986295 and standard deviation was 76.82292002. Assume that the data is normally distributed and that the bands entire collection of songs has a mean and standard deviation equal to those ...
*June 23, 2016 by Jenny*

**Algebra**

On a standardized test, the distribution of scores is normal, the mean of the scores is 75, and the standard deviation is 5.8. If a student scored 83, the student's score ranks 1. below the 75th percentile 2. above the 97th percentile 3. between the 75th percentile and the ...
*June 8, 2010 by Priscilla*

**statistics**

Section 5.3: Normal Distributions: Finding Values Answer the questions about the specified normal distribution. Q1: The lifetime of ZZZ batteries are normally distributed with a mean of 265 hours and a standard deviation ó of 10 hours. Find the number of hours that represent ...
*March 28, 2010 by looking for someone to varify my work please*

**math (statistics**

John's z-score on a college entrace exam is 1.3. If the raw scores have a mean of 480 and a standard deviation of 70 points, what is his raw score? Use a z-score formula to find John's raw score. The formula: z = (x - mean)/sd -->sd = standard deviation Using what you know ...
*January 18, 2007 by Joe*

**Math**

I. Use Chebyshev’s theorem to find what percent of the values will fall between 156 and 276 for a data set with a mean of 216 and standard deviation of 12. II. Use the Empirical Rule to find what two values 68% of the data will fall between for a data set with a mean of 219 ...
*January 21, 2011 by Tameka*

**Stats**

I. Use Chebyshev’s theorem to find what percent of the values will fall between 183 and 227 for a data set with a mean of 205 and standard deviation of 11. II. Use the Empirical Rule to find what two values 99.7% of the data will fall between for a data set with a mean of 297 ...
*October 15, 2011 by Jennifer*

**statistics**

Question: A standard placement test has a mean of 105 and a standard deviation of ó = 13. Determine the minimum sample size if we want to be 99% certain that we are within 3 points of the true mean. Answer: N = ( zc ó/E)^2 = (2.575 x 13/3)^2 = 121
*April 6, 2010 by looking for someone to varify my work please*

**Algebra**

A supervisor finds the mean number of miles that the employees in a 9the x has a line on top)department live from work. He finds X=2.9 and s=3. Which statement must be true? z376 is within 1 standard deviation of the mean. z37 is between 1 and 2 standard deviations of the mean...
*July 18, 2014 by Junior*

**finance**

The expected return on the market is 12% and the risk free rate is 7%. The standard deviation of the return on the market is 15%. Ones investor creates a portfolio on the efficient frontier with an expected return of 10%. Another creates a portfolio on the efficient frontier ...
*May 17, 2012 by benish*

**statistics**

The mean number of fitness magazines in a sample of homes is 16, the standard deviation is 5; and the mean for the number of pages of fitness magazines in a sample of homes is 43, with a standard deviation of 8. Which set of data set is more variable?
*June 25, 2011 by Nicole*

**statistics**

The average amount spent at a fast-food restaurant in California was $3.30, with a standard deviation of $.40. Yet in Georgia, the average amount spent at a fast-food restaurant was $3.25, with a standard deviation of $.10. What do these statistics tell you about fast-food ...
*March 25, 2013 by Donna*

**Statistics**

Data from the latest census was analyzed. It was determined that one-parent households spend less on food away from home that do two-parent households. The mean amount spent by 30 one-parent households is $1876 and the standard deviation is $113. The mean amount spent by 30 ...
*April 4, 2012 by Mike*

**STATISTICS(NEED HELP PLEASE?)**

Consider the following set of data. (25, 6), (25, 51), (62, 34), (84, 15), (112, 57), (122, 14) (a) Calculate the covariance of the set of data. (Give your answer correct to two decimal places.) 40.17 (b) Calculate the standard deviation of the six x-values and the standard ...
*July 25, 2012 by Kim*

**math**

A sample of 145 values is randomly selected from a population with mean, ì, equal to 45 and standard deviation, ó, equal to 23. (Give your answers correct to one decimal place.) (a) Determine the interval (smallest value to largest value) within which you would expect 99.7% of...
*June 21, 2013 by Sue7*

**stats**

One company produces movie trailers with mean 150 seconds and standard deviation 40 seconds, while a second company produces movie trailers with mean 120 seconds and standard deviation 30 seconds. What is the probability that two randomly selected trailers, one produced by ...
*January 22, 2016 by kelly*

**statistics**

Data from the latest census was analyzed. It was determined that one-parent households spend less on food away from home that do two-parent households. The mean amount spent by 30 one-parent households is $1876 and the standard deviation is $113. The mean amount spent by 30 ...
*April 18, 2012 by Mike*

**statistics**

Jack’s ACT score is 30. Jason’s SAT score is 950. Who did better? The mean SAT score is 1000 with a standard deviation of 100 SAT points. The mean ACT score is 22 with a standard deviation of 3 ACT points
*March 27, 2012 by Chris*

**Statistic**

Twenty students assigned to an experimental group receive 30 in a control 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, ...
*October 11, 2009 by Anonymous*

**Statistics**

Assume there are two lakes containing trout and the weights of the trout in each lake are normally distributed. The distribution of trout weight in Lake A has a mean of 18 ounces with a standard deviation of 2 ounces. The distribution of trout weight in Lake B has a mean of 19...
*November 24, 2011 by Brea*

**statistics**

A study found that citizens spend on average $1950 per year on groceries with a standard deviation of $100. Assume that the variable is normally distributed. 5. Identify the population mean. 6. Identify the population standard deviation. 7. Find the probability that a sample ...
*April 19, 2013 by Cam*

**Sampling Distribution**

Sampling Distribution Complete solutions and illustrations are required. 5.The standard deviation of a variable is 15. If a sample of 100 individuals are selected compute for a.The standard error of the mean. b.What sample size is necessary to double the standard error of the ...
*February 27, 2013 by Tina*

**English**

I am psueo conducting an experiment on 144 freshmen high school students who are evenly divided into 6 groups. The treatment group are receiving a new instructional strategy that the control group is not receiving. A t-test was conducted after a pre-test of a CBM measurement, ...
*August 3, 2012 by Anonymous*

**Stats**

The amount of time Ricardo spends brushing his teeth follows a Normal Distribution with unknown mean and standard deviation. Ricardo spends less than one minute brushing his teeth about 40% of the time. He spends more than two minutes brushing his teeth 2% of the time. Use ...
*October 9, 2008 by Ann*

**Math**

A friend claims that the average length of trout caught in this lake is 19 inches. To test this claim we find that a sample of 13 trout has a mean length of 18.1 inches with a sample standard deviation of 3.3 inches. The population standard deviation is unknown. If you assume ...
*December 22, 2012 by Alison*

**business statistics**

A sample of 40 investment customers serviced by an account manager are found to have had an average of $23,000 in transactions during the past year, with a standard deviation of $8500. A sample of 30 customers serviced by another account manger averaged $28,000 in transaction...
*August 4, 2009 by Heidi*

**Statistics**

What is the mean and standard deviation of 63.7%? What is the mean and standard deviation of 61.4%? Using the 68-95-99.7 rule, describe the sampling distribution of 63.7% Using the 68-95-99.7 rule, describe the sampling distribution of 61.4%? Please help I am so lost...
*October 16, 2013 by Lisa*

**Statistics**

What is the mean and standard deviation of 63.7%? What is the mean and standard deviation of 61.4%? Using the 68-95-99.7 rule, describe the sampling distribution of 63.7% Using the 68-95-99.7 rule, describe the sampling distribution of 61.4%? Please help I am so lost...
*October 17, 2013 by Lisa*

**psy**

Eric has computed that it takes an average (mean) of 17 minutes with a standard deviation of 3 minutes to drive from home, park the car, and walk to his job. One day it took Eric 21 minutes to get to work. You would use the formula for transforming a raw score in a sample into...
*February 1, 2010 by mary*

**statistics**

f someone scored two Standard Deviations above the Mean on a standardized test where the Mean = 100 and the Standard Deviation = 15, then that person’s numerical score would be…? A. 125 B. 130 C. 160 D. 90th Percentile
*February 20, 2012 by Annie*

**algebra 2**

The time it takes for climbers to reach the highest point of a mountain is normally distributed with a standard deviation of 0.75 hours. If a sample of 35 people is drawn randomly from the population, what would be the standard error of the mean of the sample?
*May 21, 2014 by bc*

**Statistics**

A driving machine was employed to hit a sample of 41 each of two different brands of golf balls using the same force each time. The research team measured the distance between the point of impact and where the ball eventually came to rest on the ground. Results are show below...
*June 21, 2010 by Randi*

**probs & stats**

A teacher gives 200 students a study guide for a test and the average score was 90 with a standard deviation of 6. She did not give the other 200 students a study guide and their average score was 70 with a standard deviation of 8. Find the critical value to determine whether ...
*May 11, 2015 by adrenning*

**statistics**

I.use the chebyshev's theorem to find out what percentage of the values will fall between 201 and 257 for a data set with a mean of 229 and standard deviation of 14. II. use the emperical rule to find out two values 68% of the data will fall between for a data set with a mean ...
*October 11, 2010 by mary*

**Math**

On a test whose distribution is approximately normal with a mean of 50 and a standard deviation of 10, the results for three students were reported as follows: Student Opie has a T-score of 60. Student Paul has a z-score of -1.00. Student Quincy has a z-score of +2.00. Obtain ...
*January 2, 2011 by Kathy*

**Stasistic**

On a test whose distribution is approximately normal with a mean of 50 and a standard deviation of 10, the results for three students were reported as follows: Student Opie has a T-score of 60. Student Paul has a z-score of -1.00. Student Quincy has a z-score of +2.00. Obtain ...
*June 20, 2011 by Ramona*

**Statistics**

I took a large sample of households in a city, and based on that, estimate the standard deviation of the income for all households in the city is $800. In order to make a desired conclusion about the income for all the households in the city, I want the sample mean for another...
*February 24, 2015 by Macy*

**Statistics and Probability**

I took a large sample of households in a city, and based on that, estimate the standard deviation of the income for all households in the city is $800. In order to make a desired conclusion about the income for all the households in the city, I want the sample mean for another...
*February 24, 2015 by Macy*

**fiance**

Sonny owns $5,000 worth of High Risk Enterprises (HRE) stock. HRE has a standard deviation of 16 percent and a beta of 2.0. He wants to invest another $5,000 and create a $10,000 portfolio that is equally as risky as the overall market. Which one of the following will ...
*October 26, 2009 by brandon*

**Math**

Sonny owns $5,000 worth of High Risk Enterprises (HRE) stock. HRE has a standard deviation of 16 percent and a beta of 2.0. He wants to invest another $5,000 and create a $10,000 portfolio that is equally as risky as the overall market. Which one of the following will ...
*October 26, 2009 by brandon*

**Investing**

Sonny owns $5,000 worth of High Risk Enterprises (HRE) stock. HRE has a standard deviation of 16 percent and a beta of 2.0. He wants to invest another $5,000 and create a $10,000 portfolio that is equally as risky as the overall market. Which one of the following will ...
*October 26, 2009 by brandon*

**statistics**

2. Why is it important to know the mean and standard deviation for a data set when applying the empirical rule? 3. If we are focused on 68% of the normal distribution, what percentage of the distribution is left in the upper tail only? 4. What value separates the 50% of the ...
*April 23, 2013 by Cam*

**Statistics**

A normal population has an expected value of 60 and a variance of 30. Use the central limit theorem to determine what the sample size should be such that the mean has a probability of 90% to fall between the values 58 and 62. One concept of the Central Limit Theorem is ...
*August 10, 2006 by ruth*

**statistics**

. For patients with a certain disease the amount of certain protein in the blood is normally distributed with a mean of 130 and a standard deviation of 5. For patients without the disease the amount of that protein is normally distributed with a mean of 150 and a standard ...
*October 29, 2014 by Anonymous*

**statistics**

For patients with a certain disease the amount of certain protein in the blood is normally distributed with a mean of 130 and a standard deviation of 5. For patients without the disease the amount of that protein is normally distributed with a mean of 150 and a standard ...
*October 30, 2014 by Anonymous*

**Statistics**

10. A teacher gives 200 students a study guide for a test and the average score was 90 with a standard deviation of 6. She did not give the other 200 students a study guide and their average score was 70 with a standard deviation of 8. Find the critical value to determine ...
*November 11, 2015 by Bert*

**Statistics**

10. A teacher gives 200 students a study guide for a test and the average score was 90 with a standard deviation of 6. She did not give the other 200 students a study guide and their average score was 70 with a standard deviation of 8. Find the critical value to determine ...
*November 11, 2015 by Bert*

**Statistics**

A school psychologist decided to separate some classes by gender to see if learning improved. She looked at studded scores on the final exam and obtained the following information: Students in boy-girl classrooms obtained an average of 71.4 on their final exams with a standard...
*April 11, 2015 by Anonymous*

**statistics**

What is the formula to do this exercise, Please. A sample of 40 investment customers serviced by an account manager are found to have had an average of $23,000 in transactions during the past year, with a standard deviation of $8500. A sample of 30 customers serviced by ...
*August 9, 2009 by Maggy*

**statistics**

1. A random sample of 100 computers showed a mean of 115 gigabytes used with a standard deviation of 20 gigabytes. What is the standard error of the mean?
*June 18, 2012 by tristen*

**algebra**

On his midterm exam, Jimmy scored 75 points, which was exactly 2 standard deviations above the mean. If the standard deviation for the test is 4, what is the mean for the test?
*October 29, 2013 by Diandra*

**statistics**

The distribution score for a city wide math test scores results in a mean of 70 and a standard deviation of 12. What score is 2 standard deviations above the mean?
*September 30, 2011 by Anonymous*

**Maths**

If I have the mean and standard deviation of data how do I work out the percentage of data within 1,2,and 3 standard deviations of the mean? :) any help would be much appreciated thanks
*October 22, 2011 by Zani*

**statistics**

It is well known that the heights of individual American men are normally distributed with mean 70 inches and standard deviation 2.8 inches. The Central Limit Theorem states that if n men are randomly chosen, then their average height will also be normally distributed with ...
*February 13, 2011 by LISA*

**stats **

Relatively speaking, which statistics exam did you do better on? On your first statistics exam you scored a 72 and on the second exam you scored an 89. Hey, you’re improving! Or are you? On the first exam, the class mean was 71 with a standard deviation of 15. On the second ...
*February 5, 2013 by kelly*

**Stats**

A study found that for adults the general self-efficacy scale mean score was 35 and standard deviation was 12. A group of clients (n=14) was measured for their general self-efficacy with the same measure and found having 40 with standard deviation of 20. A group of therapist ...
*August 17, 2013 by Mark*

**statistics**

The purchasing department has suggested that all new computer monitors for your company should be a new design. You want data to assure you that employees will like the new monitors. The next 20 employees needing a new computer are the subjects for an experiment. (a) Label the...
*November 2, 2012 by appy*

**Math (statistics)**

The probability of obtaining heads on a biased coin is 0.4. The coin is tossed 600 times. a. i. Write down the mean number of heads (240) ii. Find the standard deviation of the number of heads (12) b. Find the probability that the number of heads obtained is less than one ...
*March 16, 2016 by Myra*

**Statistics**

In recording the self-reported lengths of a particular body part in a sample of male undergraduates, the largest was claimed to be 20 cm—a full 3 standard deviations from the mean length for the sample. The shortest alleged length was only 10 cm, which was equivalent to ...
*November 3, 2012 by susan*

**Statistics**

You are wondering whether male or female students pay more for books and materials at the U of C. You find 5 male friends at the U of C and find that they spent an average of $680 with a standard deviation of $5. You find 4 female friends at the U of C and find that they spent...
*December 2, 2012 by Susan*

**statistics**

say that you have a distribution of exam scores with a mean of 57 and a standard deviation of 7. if a student in the class has a standard score equal to 2.429, what would their raw score on the exam be?
*December 2, 2012 by Dawn*

**Operations management**

An appliance manufacturer wants to contract with a repair shop to handle authorized repairs. The company has an acceptable range of repair time from 50 minutes to 90 minutes. Two firms have submitted bids for the work. In the evaluation trail, one firm had a mean repair time ...
*February 13, 2012 by Ashley*

**Statistics**

The law of large numbers tells us what happens in the long run. Like many games of chance, the numbers racket has outcomes so variable - one three-digit number wins $600 and all others win nothing - that gamblers never reach "the long run." Even after many bets, their average ...
*February 25, 2014 by Ray*

**Statistics**

The law of large numbers tells us what happens in the long run. Like many games of chance, the numbers racket has outcomes so variable - one three-digit number wins $600 and all others win nothing - that gamblers never reach "the long run." Even after many bets, their average ...
*February 25, 2014 by Ray*

**Statistics**

The law of large numbers tells us what happens in the long run. Like many games of chance, the numbers racket has outcomes so variable - one three-digit number wins $600 and all others win nothing - that gamblers never reach "the long run." Even after many bets, their average ...
*February 25, 2014 by PLEASE HELP!!!!!!!!!*

**statistics**

show that in the binomial distribution (q+p)^n the ratio of the mean deviation about about the mean to standard deviation is 2/(npq)^0.5*n-1 cµ-1p^µ-1 q^n-µ where µ is the greatest integer contained in np+1 . find the limits of the above ratio as n tends to infinity.
*January 10, 2012 by urmila*

**STATISTICS**

Can someone please tell me how to solve this problem? A buyer for a lumber company must determine wheter to buy a piece of land containing 50,000 trees. if 2000 tress are at least 48 feet tall she will purchase the land; otherwise she will not. the owner of the land reports ...
*April 20, 2007 by DEE-DEE*

**Statistics**

In testing a new drug, researchers found that 20% of all patients using it will have a mild side effect. A random sample of 25 patients using the drug is selected. Find the mean and standard deviation of patients having a mild side effect. Mean = np = 25(.2) = 5 Ok Standard ...
*March 11, 2016 by Ray *

**statistics**

The actual weights of bag of pet food are normally distributed.The mean of the weights is 50.0 lb,with a standard deviation of 0.2 lb. C)In a group of 50 bags,how many would yu expect to be within 1.5 standard deviations of the mean?
*June 4, 2012 by Anonymous*

**Math**

Question An investor puts $15,000 into each of four stocks, labeled A, B, C, and D. The table shown below contains the means and standard deviations of the annual returns of these four stocks. Stock Mean Annual Return Standard Deviation of Annual Return A 0.15 0.05 B 0.18 0.07...
*October 15, 2013 by Kessy*

**Statistics**

The average mpg usage for a 2004 Ford Expedition 2WD for a sample of 10 tanks of gas was 17.0with a standard deviation of 0.8. For a Ford Explorer 2WD, the average mpg usage for a sample of 10 tanks of gas was 18.5 with a standard deviation of 1.0. (a) Assuming equal variances...
*September 19, 2010 by Kim*

**bus/stats**

a sample of the personal files of eight male employees revealed that, during a six-month period, they lost the following number of days due to illness: 2,0,6,3,10,4,1 and 2. Calculate the standard deviation of the above sample? the means deviation is 2.375? but not sure how to...
*September 3, 2011 by tim*

**math**

lilly made a 75 on her history test and an3 on her math test. the mean grade on the history test was 72 with a standard deviation of 5. the average grade on the math test was 81 with a standard deviation of 4. which test did lilly do better?
*May 21, 2015 by debbie*

**statistics**

Prep Courses? Scores for men (nationwide) on the verbal portion of the SAT test are normally distributed with a mean of 509 and a standard deviation of 112. Randomly selected men are given the Columbia review course before taking the SAT test. After the course, a sample of 49 ...
*June 28, 2010 by STatistic*

**Stat/trig question, please help me, thanks**

In 1995, more than 1.1 million students in the U.S. took the SAT. On the mathematics section, the mean =507, s=112 (standard deviation). Students recieve scores rounded to the nearest 10. What is the interval of student scores that lie within one standard deviation of the mean...
*September 5, 2006 by christine*

**business statistics**

Please can you give the formula to do this exercise, Thank you. A sample of 40 investment customers serviced by an account manager are found to have had an average of $23,000 in transactions during the past year, with a standard deviation of $8500. A sample of 30 customers ...
*August 10, 2009 by Heidy*

**statistics**

Farmer Max, sells grain to Germany, owns 60 acres of wheat fields. Based on the past experience, he knows that the yield from each individual acre is normally distributed with mean 120 bushels and standard deviation 12 bushels. Help Farmer Max plan for his next year crop by ...
*November 23, 2014 by loh*

**Math**

3.22 Defective rate. A machine that produces a special type of transistor (a component of computers) has a 2% defective rate. The production is considered a random process where each transistor is independent of the others. (a) What is the probability that the 10th transistor ...
*February 11, 2016 by Anonymous*