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August 30, 2015

Search: standard deviation

Number of results: 8,899

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, ě, 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

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

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

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

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
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

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
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

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

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
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

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

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

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

statistics
Suppose that the population standard deviation (ó) for a normally distributed standardized achievement test (ACT) is 6. What would the standard error of the sample mean (óxbar) be if we were to draw a random sample of 36 test scores?
October 4, 2011 by Anonymous

business statistics
Please can you give the formula 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 another account...
August 9, 2009 by Heidy

statistics
An investment broker reports that the yearly returns on common stocks are approximately normally distributed with a mean return of 12.4 percent and a standard deviation of 20.6 percent. On the other hand, the firm reports that the yearly returns on tax-free municipal bonds are...
February 19, 2012 by Anonymous

statistics
Suppose that the percentage returns for a given year for all stocks listed on the New York Stock Exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n= 5 stocks from the ...
August 31, 2009 by Amy

Statistics
Suppose that the percentage returns for a given year for all stocks listed on the New York Stock Exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n= 5 stocks from the ...
June 7, 2010 by Mary

Statistics
Suppose that two different tests A and B are to be given to a student chosen at random from a certain population. Suppose also that the mean score on test A is 85, and the standard deviation is 10; the mean score on test B is 90, and the standard deviation is 16; the scores on...
February 16, 2011 by Charles

statistics
A widget factory's worker productivity is normally distributed. one worker produces an average of 75 widgets per day with a standard deviation of 20. another worker produces at an average rate of 65 per day with standard deviation of 21. 1)what is the probability that in any ...
April 29, 2012 by Anonymous

statistics
Suppose that the percentage returns for a given year for all stocks listed on the new york stock exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n=5 stocks from the ...
November 9, 2009 by ileana

statistics
Use the Standard Normal Distribution table to find the indicated area under the standard normal curve. Q1: Between z = 0 and z = 2.24 A1: 0 = 0.5000 2.24 = 0.9875 0.9875 – 0.5000 = 0.4875 Q2:To the left of z = 1.09 A2: 0.8621 Q3: Between z = -1.15 and z = -0.56 A3: -1.15 = 0....
March 27, 2010 by looking for someone to varify my work please

Stats
The director of admissions at Kinzua University in Nova Scotia estimated the distribution of student admissions for the fall semester on the basis of past experience. Admissions Probability 1,080 0.5 1,340 0.2 1,660 0.3...
September 28, 2010 by Nicole

statistics
The Frayed Nerves Anxiety Scale (FNAS) is used to measure the anxiety level of people on a scale from 0 to 1000. Four students were randomly chosen and given the FNAS before their second exam. Their scores were 700, 653, 740, and 707. The standard deviation sigma of the test ...
October 17, 2011 by Anand

Statistics
I have a question that involves explaining what is wrong in each of the following situations: (a) A random sample of size 20 is taken from a population that is assumed to have a standard deviation of 12. The standard deviation of the sample mean is 12/20. (b) A researcher ...
March 29, 2009 by Lynn

statistics
3. The personnel director of a corporation will study the overtime work during the previous year for the 2,575 clerical workers. A sample of 100 of these workers will be chosen at random from the files. The average and the standard deviation of the overtime hours will be ...
May 8, 2014 by Maura

Sociology (stats) help
Given the mean = $12 Standard deviation = $2.50 Suppose that a large state university graduate research assistants are paid by the hour. Data from the personnel office show the distribution of hourly wages paid to graduate students across the campus is approximately normal ...
October 8, 2014 by Ronald

math
select ten (10) states and calculate the mean and standard deviation for average insurance costs. Next, calculate the mean and standard deviation for average insurance costs for all 51 states. Compare and contrast the means and standard deviations for the ten (10) states you ...
January 20, 2015 by Mary Ann

statistics
A Coach found the correlation between physical fitness and athletic ability to be r=.65. the mean and standard deviation of the physical fitness test was 330, 50. the mean and standard deviation of the athletic ability test was 9, 2. If you have a physical fitness score of 350...
November 16, 2014 by Nicole

math
Our statistics students, as noted were asked to rate their admiration of Hillary Rodham Clinton on a scale of 1 to 7. They also were asked to rate their admiration of Jennifer Lopez and Venus Williams on a scale of 1 to 7. As noted earlier, the mean rating of Clinton was 4.06...
October 14, 2013 by eid2013

sattistics
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 ...
July 18, 2009 by Jerry

Statistic
18. 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 ...
February 20, 2010 by Doris I

math
Our statistics students, as noted in Exercise 6.32, were asked to rate their admiration of Hillary Rodham Clinton on a scale of 1 to 7. They also were asked to rate their admiration of Jennifer Lopez and Venus Williams on a scale of 1 to 7. As noted earlier, the mean rating of...
October 12, 2013 by eid2013

statistics
A statistics practitioner would like to estimate a population mean to within 50 units with 99% confidence given that the population standard deviation is 250. a) What sample size should be used. b) Repeat part (a) with a standard deviation of 50. c) Repeat part (a) using a 95...
March 13, 2010 by Tom

Elementary Statistics
Heights of women have a bell-shaped distribution with a mean of 161 cm and a standard deviation of 7 cm. Using Chebyshev’s theorem, what do we know about the percentage of women with heights that are within 2 standard deviations of the mean? What are the minimum and maximum ...
September 4, 2012 by mary

El camino college:math
The xyz corporation claims that there's NO DIFFERENCE in the salary of female and male workers at the Southern California plant. A human rights agency took two samples(25 each) .the male sample gad a mean of 350per week wit standard deviation of 50. The female sample had a ...
August 4, 2015 by Alma

statistics help please
For a random sample of 10 men, the mean head circumference is x = 57.3 cm and the sample standard deviation is s = 2 cm. The standard error of the sample mean is: a. 0.200 b. 0.447 c. 0.500 d. 0.632
July 22, 2011 by toyman

Stastics
If the population standard deviation is Ợ=8, how large a sample is necessary to have a standard error that is a. Less than 4 points? b. Less than 2 points? c. Less than 1 point?
December 13, 2013 by Lyndyc

Math
Can someone help me verify if this is correct? Gasoline usage for compact cars in Canada is a normal distribution with a mean of 33.3 km/l and with standard deviation of 7.3 km/L. Round your answers to one decimal place. a) What percentage of compact cars obtains 20km/L or ...
April 17, 2011 by Jay

Math
Can someone help me verify if this is correct? Gasoline usage for compact cars in Canada is a normal distribution with a mean of 33.3 km/l and with standard deviation of 7.3 km/L. Round your answers to one decimal place. a) What percentage of compact cars obtains 20km/L or ...
April 17, 2011 by Jay

statistics
The diameter of an electric cable is normally distributed, with a mean of 0.6 inch and a standard deviation of 0.02 inch. What is the probability that the diameter will exceed 0.62 inch? (You may need to use the standard normal distribution table.
June 4, 2014 by leelee kay

statistics
A standardized third grade reading test, called the We Can Read Test, has a mean of 50 with a standard deviation of 10. A developmental psychologist conducts a study, where he assesses the reading ability of a random sample of 75 third graders using the We Can Read Test, and ...
April 16, 2014 by Carrie

Statistics
I am so lost on this statistics question would someone help me figure out how to answer it? A random variable X is normally distributed with the mean and standard deviation 1.6. What is the proportion of the data values that lies within 1.6 standard deviations from the ...
November 27, 2012 by Layney

statistics
Question2: When parking a car in a downtown parking lot, drivers pay according to the number of hours or fraction thereof. The probability distribution of the number of hours cars are parked is given below X 1 2 3 4 5 6 7 8 f(X) 0.30 0.24 0.17 0.10 0.08 0.05 0.04 0.02 a. ...
December 11, 2011 by s.Alhosani

statistics
Our statistics students, as noted were asked to rate their admiration of Hillary Rodham Clinton on a scale of 1 to 7. They also were asked to rate their admiration of Jennifer Lopez and Venus Williams on a scale of 1 to 7. As noted earlier, the mean rating of Clinton was 4.06...
October 14, 2013 by eid2013

algebra 2
The monthly rents for the apartments in a building are listed below. $425, $550, $550, $550, $650, $650, $650, $650, $800, $900 Part A: Find the mean, median, mode, range, and standard deviation of the rents. Part B: The apartment manager considers raising the rent for every ...
May 23, 2012 by jenny

Math
If the population standard deviation is   8, how large a sample is necessary to have a standard error that is: a. less than 4 points? b. less than 2 points? c. less than 1 point?
February 1, 2013 by Tracy

math
On a standardized test, Ann received a score of 85, which was exactly 2 standard deviations about the mean. If the standard deviation for the test is 4, what is the mean for this test?
May 20, 2015 by debbie

statistics
The mean length of a work week for the population of workers was reported to be 39.2 hours. Suppose that we would like to take a current sample of workers to see whether the mean length of a work week has changed from the previously reported 39.2 hours. a. State the hypotheses...
April 29, 2012 by frances

Math
1)Find the standard deviation of the data set to the nearest tenth. (21,13,18,16,13,35,12,8,15) A)16.8 B)7.8 C)7.3 D)5.7 I chose C mean = 21+13+18+16+13+35+12+8+15/9 16.8 variance = (21-16.8)^2 = 17.64...did that with the rest and added them to get sqrt 53.7 standard deviation...
February 23, 2008 by Jon

math
Suppose a test of musical ability has a normal distribution with a mean of 50 and a standard deviation of 5. Approximately what percentage of people are over 55? a. 6% b. 16% c. 45% d. 84% A z-score of 1.75 indicates how many standard deviation units above the mean? a. 1.75 b...
May 8, 2010 by Amanda

Statsistics
You are testing the claim that the mean GPA of night students is less than the mean GPA of day students. You sample 45 night students, and the sample mean GPA is 2.18 with a standard deviation of 0.31 You sample 30 day students, and the sample mean GPA is 1.97 with a standard ...
May 4, 2015 by hannah

Statistics- Math
One student scored 54 on a math test for which the mean score was 50.5 and the standard deviation was 3.2. Another student scored 80 on a chemistry test for which the mean score was 75.2 and the standard deviation was 5.2. Which student (math or chemistry) had a "better" score...
February 17, 2012 by Kerrin

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