Wednesday
October 1, 2014

Search: Standard Deviation

Number of results: 8,038

statistics
According to a bank, the time taken by its customers to use cash dispensing machines is normally distributed with a mean of 18 seconds and a standard deviation of 3 seconds. I) What is the probability that a customer selected at random takes less than 13 seconds? II) Find the ...
November 5, 2011 by victor

stats.
The GMAT test is required for admission to most graduate programs in business. In a recent year, the GMAT test scores were normally distributed with a mean of 550 and standard deviation of 100. A. Find the first quartile for the distribution of GMAT scores. B. Find the median ...
March 18, 2013 by Christina

statistics
The grades on the final examination given in a large organic chemistry class are normally distributed with a mean of 72 and a standard deviation of 8. The instructor of this class wants to assign an A grade to the top 10% of the scores, a B grade to the next 10% of the ...
March 24, 2013 by Sarah

statistics
The Graduate Record Exam (GRE) has a combined verbal and quantitative mean of 1000 and a standard deviation of 200. Scores range from 200 to 1600 and are approximately normally distributed. What percentage score above 1300? What percentage score above 800? What percentage ...
September 21, 2014 by Jeremy

Statistics
The head librarian claims that books have been checked out an average of seven times in the last year. You suspect she has exaggerated the checkout rate and that the mean number of checkouts per book per year is, in fact, less than seven. Using the computerized card catalog, ...
May 2, 2008 by Lindy

Statistics
A person's level of blood glucose and diabetes are closely related. Let x be a random variable measured in milligrams of glucose per deciliter (1/10 of a liter) of blood. Suppose that after a 12-hour fast, the random variable x will have a distribution that is approximately ...
June 20, 2010 by Alex

statistics
A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 440 seconds and a standard deviation of 60 seconds. Find the probability...
March 1, 2011 by jackie

Psychology
A distribution has a standard deviation of _ _ 12. Find the z-score for each of the following locations in the distribution. a. Above the mean by 3 points. b. Above the mean by 12 points. c. Below the mean by 24 points. d. Below the mean by 18 points.
January 21, 2012 by Sharon

Statistics
A random sample of 51 of the largest companies in the united states gave the following P/e ratios 11 35 19 13 15 21 40 18 60 72 9 20 29 53 16 26 21 14 21 27 10 12 47 14 33 14 18 17 20 19 13 25 23 27 5 16 8 49 44 20 27 8 19 12 31 67 51 26 19 18 32 Use a calculator with mean and...
June 11, 2011 by Anonymous

Statistics
A random sample of 51 of the largest companies in the united states gave the following P/e ratios 11 35 19 13 15 21 40 18 60 72 9 20 29 53 16 26 21 14 21 27 10 12 47 14 33 14 18 17 20 19 13 25 23 27 5 16 8 49 44 20 27 8 19 12 31 67 51 26 19 18 32 Use a calculator with mean and...
June 11, 2011 by Anonymous

statistics
A random sample of 51 of the largest companies in the united states gave the following P/e ratios 11 35 19 13 15 21 40 18 60 72 9 20 29 53 16 26 21 14 21 27 10 12 47 14 33 14 18 17 20 19 13 25 23 27 5 16 8 49 44 20 27 8 19 12 31 67 51 26 19 18 32 Use a calculator with mean and...
June 11, 2011 by Anonymous

statistics
A random sample of 51 of the largest companies in the united states gave the following P/e ratios 11 35 19 13 15 21 40 18 60 72 9 20 29 53 16 26 21 14 21 27 10 12 47 14 33 14 18 17 20 19 13 25 23 27 5 16 8 49 44 20 27 8 19 12 31 67 51 26 19 18 32 Use a calculator with mean and...
June 11, 2011 by Anonymous

Math please help!
According to a student project for statistics 250, the amount of money spent on texts per semester by the population of students at a small liberal arts college is normally distributed with a mean of $426 and a standard deviation of $54. Determine the percent of all samples of...
October 30, 2008 by Mary

statistics
Information given:the distribution of male head circumference (HC) is normal with a mean of 56cm and a standard deviation of 1.8cm first question -the prob that HC of a random chosen man is larger than 57.8cm is? Work: pr(x)>57.8cm z=(57.8-56)=1.8--->.9641 i got it wrong...
April 15, 2010 by UPD

Stats
nformation given:the distribution of male head circumference (HC) is normal with a mean of 56cm and a standard deviation of 1.8cm first question -the prob that HC of a random chosen man is larger than 57.8cm is? Work: pr(x)>57.8cm z=(57.8-56)=1.8--->.9641 i got it wrong...
April 15, 2010 by UPD

Math grd 12
The number of nuts in a package of Nutty's premium cashews is normally distributed with mean of 432.4 nuts and standard deviation of 5.8 nuts packages with fewer than 420 nuts or more than 445 nuts will be rejected by quality control a) what is the probability that a package ...
January 19, 2011 by Celina

stats
The percent of fat calories that a person that in America consumes each day is normallydistributed with a mean of 36 and a standard deviation of 10. Suppose that 16 individuals are randomly chosen for an experiment. 1. Completely describe the distribution of sample means for ...
April 28, 2013 by Kayla

Statistics
An IQ test is designed so that the mean is 100 and the standard deviation is 19 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 95% confidence that the sample mean is within ...
February 12, 2014 by Stephanie

FINANCE
Assume the returns from holding small-company stocks are normally distributed. Also assume the average annual return for holding the small-company stocks for a period of time was 16.5 percent and the standard deviation of those stocks for the period was 32.5 percent. Use the ...
April 2, 2014 by Alec

statistics
A human resources manager wants to determine a confidence interval estimate for the mean test score for the next office-skills test to be given to a group of job applicants. In the past, the test scores have been normally distributed with a mean of 74.2 and a standard ...
June 19, 2013 by Rald

Stats
A new extended-life light bulb has an average service life of 750 hours, with a standard deviation of 50 hours. If the service life of these light bulbs approximates a normal distribution, about what percent of the distribution will be between 600 and 900 hours? a. 95 percent...
December 13, 2011 by Stephanie F

statistics
An agricultural economist is interested in determining the average diameter of peaches produced by a particular tree. A random sample of 50 peaches is taken and the sample mean calculated. Suppose that the average diameter of peaches on this tree is known from previous years' ...
March 26, 2012 by Pat

Statistics
The Boeing 757-200 ER airliner carries 200 passengers and has doors with a height of 72 inches. Heights of men are normally distributed with a mean of 69 inches and a standard deviation of 2.8 inches. b) assume that half of the 200 passengers are men, what doorway height ...
April 8, 2013 by Liz

Finance
Veggie Burgers, Inc., would like to maintain its cash account at a minimum level of $246,400; but expect the standard deviation in net daily cash flows to be $13,600; the effective annual rate on marketable securities to be 4.8 percent per year; and the trading cost per sale ...
May 15, 2010 by Hans

HELP MATH
lee looked at the results of an exam he had just given to his grade 2 math class. he saw that louise had a score of 95%. he also saw that the standard deviation for the test was 0. if arif was also in his grade 2 math class, what mark did arif get on the exam?
January 6, 2011 by Anonymous

Chem
This is also from the lab concerning activity serious of metals and calculation of electrode portentions... Question: What are the standard conditions for measuring potentials? Does that mean... Standard condition for temp: 298K Concentration: 1 molar concentration Pressure: 1...
March 28, 2007 by Marisol

Finance
21. Consider an economy with two types of firms, S and I. S firms all move together. I firms move independently. For both types of firms, there is a 60% probability that the firms will have a 15% return and a 40% probability that the firms will have a -10% return. What is the ...
August 2, 2010 by Anonymous

Statistics
According to a study by the Centers for Disease Control, the national mean hospital stay after childbirth is 2.1 days. Reviewing records at her own hospital, a hospital administrator calculates that the mean hospital stay for a random sample of 81 women after childbirth is 2.3...
November 9, 2013 by Michael

statistics
A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is 15. a) Compute the 95 % confidence interval for the population mean. b) Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence ...
April 7, 2011 by TIMBERLY

Statistics
. A random sample is selected from a normal population with a mean of __40 and a standard deviation of __10. After a treatment is administered to the individuals in the sample, the sample mean is found to be M _ 42. a. How large a sample is necessary for this sample mean to be...
January 26, 2012 by Sharon

English
How do you know whan a word is in standard or non-standard Canadian English? Many dictionaries contain this information. If you live in Canada, please check your library for a dictionary that shows standard and non-standard Canadian usage. Also -- Dictionary.com (and other ...
October 18, 2006 by Gina

Accounting Math
A standard costing system is the traditionally used costing system. It has two main purposes: cost control and product costing. Standard costs are determined by accountants working together with other employees of the organization. Which employees outside of accounting do you ...
June 20, 2013 by Tameika

Math-Statistics-please doublecheck my answers
In the fall of 2000, 54% of the almost 34,000 first-year students attending one of the California State Universities had strong enough math skills to take an entry level course. 1)Based on a sample of 20 students, can we assume our calculations will be accurate? My answer is: ...
January 31, 2012 by Mandy

Statistics
The average annual salary of employees at Wintertime Sports was $28,750 last year. This year the company opened another store. Suppose a random sample of 18 employees had an average annual salary of $25,810 with standard deviation of s = $4230. Use a 1% level of significance ...
March 25, 2012 by Jasmine

Statistics
A random sample of 16 mid-sized cars tested for fuel consumption gave a mean of 26.4 kilometers per liter with a standard deviation of 2.3 kilometers per liter. i) Assuming that the kilometers per liter given by all mid-sized cars have a normal distribution, find a 99% ...
May 11, 2012 by Nesa

STAT 250 Probability
Final averages are typically approximately normally distributed with a mean of 66 and a standard deviation of 10.5. Your professor says that the top 5% of the class will receive an A; the next 15%, a B; the next 47%, a C; the next 22%, a D; and the bottom 11%, an F. (a) What ...
March 20, 2013 by Jane Segurra

STAT 250 Probability
Final averages are typically approximately normally distributed with a mean of 66 and a standard deviation of 10.5. Your professor says that the top 5% of the class will receive an A; the next 15%, a B; the next 47%, a C; the next 22%, a D; and the bottom 11%, an F. (a) What ...
March 20, 2013 by Jane Segurra

Chemistry
Tap water is measured for arsenic and found to have a mean signal of 0.006065. Next, a small amount of Arsenic is spiked into the tap water such that the new value is 0.50ppb higher than before. The mean signal from this new low-level concentration is 0.0391, with a standard ...
December 10, 2011 by Ken

Word Problem
Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below. The firm examined 35 randomly chosen fax transmissions during the next year...
September 28, 2008 by Marilyn

Math
The image of the public library is constantly changing, and their online services continue to grow. Usage of the library's home page grew by 17% during the past 12 months. It has been estimated that the current average length of a visit to the library's homepage is ...
June 22, 2013 by JACKIE

math
A company is considering implementing one of two quality control plans for monitoring the weights of automobile batteries that it manufactures. If the manifacturing process is working properly, the battery weights are approximatedly normally distributed with a specified mean ...
October 3, 2007 by Anonymous

statistics
Please only the formula and steps to do this problem. Thank you An assembly process includes a torque wrench device that automatically tightens compressor housing bolts; the device has a known process standard deviation of = 3 lb-ft in the torque applied. A simple random ...
August 2, 2009 by Lina

statistics
if a test has a mean of 150 and a standard deviation of 30, we know that: a)50% of the respondents scored between 180 and 210 b)68% of the responents scored above 120 c)50% of the respondents scored between 120 and 210 d) 96% of the respondents scored between 90 and 210
November 21, 2012 by carly

Probabilty & Statistic
A random sample is selected from a normal population with a mean of __40 and a standard deviation of __10. After a treatment is administered to the individuals in the sample, the sample mean is found to be M _ 42. a. How large a sample is necessary for this sample mean to be ...
January 23, 2012 by Sharon

math
a tire manufacturer believes that the tread life of its tires are normally distributed and will lst an average of 60,000 miles with a standard deviation of 3,000 miles. sixty-four randomly selected tires were tested and the average miles where the tire failed were recorded. ...
May 31, 2011 by monk

statistics
A survey was conducted to measure the number of hours per week adults spend on home computers. In the survey, the number of hours was normally distributed, with a mean of 8 hours and a standard deviation of 1 hour. A survey participant is randomly selected. Find the ...
November 7, 2011 by lindsay

statistics
It is known that the population mean for the Full Scale IQ of the WAIS is 100 with a standard deviation of 15. A researcher assesses a sample of 200 adults and find that they have a mean Full Scale IQ of 102. The point estimate of the mean for this group is ___________ and the...
April 15, 2014 by Katie

Finite math
Scores for men on the verbal portion of the SAT-I test are normally distributed with a mean of 509 and a standard deviation of 112. (a) If 1 man is randomly selected, find the probability that his score is at least 579. (b) If 13 men are randomly selected, find the probability...
June 2, 2014 by Preet

Math Helppp
Scores for men on the verbal portion of the SAT-I test are normally distributed with a mean of 509 and a standard deviation of 112. (a) If 1 man is randomly selected, find the probability that his score is at least 579. (b) If 13 men are randomly selected, find the probability...
June 2, 2014 by TJ

Statistics
. A certain company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a battery is normally distributed, with a mean of 45 months and a standard deviation of 7 months. If the company does not want to make refunds for ...
June 20, 2010 by Jacob

chemistry
You need to determine the concentration of a sulfuric acid solution by titration with a standard sodium hydroxide solution. You have a 0.1896 M standard solution. You take a 25.00 mL sample of the original acid solution and dilute it to 250.0 mL. You then take a 10.00 mL ...
April 11, 2014 by Steven

Statistics
A colleges data about the incoming freshmen indicates that the mean of their high school GPAs was 3.4, with a standard deviation of 0.35; the distribution was roughly mound-shaped and only slightly skewed. The students are randomly assigned to freshman writing sem- inars in ...
January 25, 2013 by Lissa

math help
Consider the approximately normal population of heights of male college students with mean = 69 inches and standard deviation of = 4.6 inches. A random sample of 25 heights is obtained (e) Find P(x > 70). (Give your answer correct to four decimal places.) (f) Find P(x &...
June 16, 2013 by Sue 7

statistics 201
A firm hires a pool of financial consultants to discuss portfolio recommendations with its clients. The CEO believes that another financial consultant should be hired if the average phone consultation exceeds 350 seconds. A random sample of 100 phone calls revealed a mean of ...
November 21, 2013 by lea

maths
if i have k = 36.86 +/- 4.78 and v = 113 +/- 9.92 both using 95% confidence limits and no true values of k or v given am i right in saying that accuracy cannot be determined and that v is a more precise measurement my question was to comment on what can be said about the ...
January 19, 2010 by lucy

statistics
You are the manager at a company and are asked to present a report on the year-to-date performance of your division. What type of statistical information would you include in your report? In paticular, which descriptive statistics (mean,median, standard deviation,etc.) do you ...
June 21, 2011 by triplec

Stats
a teacher teaches two sections (A and B) of a class. Both sections have a mean score of 75. Section A only has 5 students and they all received a score of 75, while section B has 15 students with a mean score of 75 with a variance of 12. What is the standard deviation of the ...
May 28, 2008 by Andrea

Statistics NEEED YOUR HELP ASAP!!!!!!!!!!!!!!
The manufacturer of the X-15 steel-belted radial truch tire claims that the mean mileage the tire can be driven before the tread wears out is 80,000 km. The standard deviation of the mileage is 8,000 km. The Crosset Truck Company bought 48 tires and found that the mean mileage...
April 3, 2010 by Samir

Statistics
Are you annoyed with spam e-mail? Suppose a random sample of 200 Kent State students was asked this question of which 80% said that they are annoyed. From the provided information we can find the following: sample percent = 80% (sample proportion = .80) standard deviation (S.D...
July 9, 2012 by Sheri

college stats
can someone please explain the steps: suppose that the grade point average,denoted by X,of a university student is Normally distributed with the mean 2.786 and standard deviation 0.375 A). a student is on the deans list if her GPA exceeds 3.746. What percent of the students ...
October 1, 2012 by damon

Statistics
1. Use the following to answer questions: The table below presents the probability distribution for X = the number of email messages you will receive in the next 10 minutes. (9 pts) X 0 1 2 3 P(X) .35 .35 .25 .05 a. What is the probability that no emails will be received? b. ...
March 3, 2010 by Denise

statistics
The general manager for Gordon's Self Service Gasoline is interested in estimating the mean number of gallons of gasoline that are purchased by customers at their Philadelphia location. He would like his estimate to be within plus or minus 0.50 gallons, and he would like the ...
April 18, 2012 by Melvin

statistics
A study of peach trees found that the average number of peaches per tree was 625. The standard deviation of the population is 140 peaches per tree. Ascientist wishes to find 80% confidence interval for the mean number of peaches per tree. How many trees does she need to sample...
June 18, 2013 by betsy

statistics
Professor Smith conducted a class exercise in which students ran a computer program to generate random samples from a population that had a mean of 50 and a standard deviation of 9mm. Each of Smith's students took a random sample of size n and calculated the sample mean. Smith...
February 16, 2008 by lauren

statistics
sat scores around the nation tend to have a mean score of about 500, a standard deviation of 100 points and are approximately normal distribution. a person who score 600 on the sat has approximately what percentile rank within the population? show all calculations. 600-500/100...
October 16, 2010 by mary

Statistics
5. Scores on a recent national statistics exam were normally distributed with a mean of 80 and a standard deviation of 6. a. What is the probability that a randomly selected exam will have a score of at least 71? b. What percentage of exams will have scores between 89 and 92? ...
March 5, 2012 by Zac

social science statistics
a professor was curious to whether the students in a very large class she was teaching who turned in their first scored differently from the overall mean on the test.The overall mean score on the test was 75 with a standard deviation of 10;the score were approximately normally...
April 9, 2013 by mike

Statistics
From past experience, an airline has found the luggage weight for individual air travelers on its trans-Atlantic route to have a mean of 80 pounds and a standard deviation of 20 pounds. The plane is consistently fully booked and holds 100 passengers. The pilot insists on ...
September 30, 2009 by Mariah

Statistics
From past experience, an airline has found the luggage weight for individual air travelers on its trans-Atlantic route to have a mean of 80 pounds and a standard deviation of 20 pounds. The plane is consistently fully booked and holds 100 passengers. The pilot insists on ...
October 3, 2009 by JOSH

statistics
From past experience, an airline has found the luggage weight for individual air travelers on its trans- Atlantic route to have a mean of 80 pounds and a standard deviation of 20 pounds. The plane is consistently fully booked and holds 100 passengers. The pilot insists on ...
June 18, 2011 by cedreana

statistics
A maker of tires for cars has a multitude of data to support the fact that the lifetime of their tires follows a normal distribution with a mean of 42,100 miles and a standard deviation of 2,510 miles. Find the probability that a randomly selected tire will have a lifetime of ...
May 9, 2008 by Tanya

Statistics
Standard Normanl Drill: A. Find the number z such that the proportion of observations that are less than z in a standard Normal distribution is 0.8. B. Find the number z such that 35% of all observations from a standard Normal distribution are greater than z. i have now idea ...
September 10, 2007 by Devon

statistics
Assume that women's heights are normally distributed with a mean given by u=64.6 in and a standard deviation given by 0=2.8in. a) If 1 woman is randomly selected, find the probability that her height is less than 65in. b) If 49 women are randomly selected, find the probability...
November 7, 2013 by angela

chemistry
calculate the standard molar entropy change for the combustion of methane gas using S naught values from standard thermodynamic tables. Assume that liquid water is one of the products.
October 5, 2012 by Bru

statistics
3. The mean volume of draught beer served in pint glasses in a particular pub is known to be 0.564 litres. A consumer organization takes a random sample of 64 pints of draught beer and finds that the standard deviation of this sample is 0.025 litres. What is the probability ...
November 5, 2011 by najma

statistics
1. A random sample of n = 16 scores is selected from a normal distribution with a mean of = 50 and a standard deviation of = 10. What is the probability that the sample mean will have a value between 45 and 55? What is the probability that the sample mean will have a value...
May 5, 2011 by jansa

statistics
one of the major U.S. tire makers wishes to review its warranty for their rainmaker tire. The warranty is for 40,000 miles. The tire company beleives that the tire actually lasts more than 40,000 miles. A sample of 49 tires reveales that the mean number of miles is 45,000 ...
May 16, 2011 by c

College Stats
A machine fills 64 ounce detergent jugs. It is known that the net amount of detergent poured into each jug has a normal distribution with a standard deviation of 0.35 ounces. The inspector wants to adjust the machine such that at least 95% of the jugs have more than 64 ounces ...
October 28, 2008 by Riley

Psychological Statistics
Assume that GRE scores approximate a normal curve and have mean of 500 points and a standard deviation of 100. What proportion of the normal curve would correspond to each of the following situations? 1) A score more than 50 points above the mean? 2) A score more than 100 ...
September 22, 2012 by Vidhi

math, statistics
The image of the public library is constantly changing, and their online services continue to grow. Usage of the library's home page grew by 17% during the past 12 months. It has been estimated that the current average length of a visit to the library's homepage is ...
June 10, 2014 by BJ

statistics
The pucks used by the National Hockey League for ice hockey must weigh between 5.5 and 6.0 ounces. Suppose the weights of pucks produced at a factory are normally distributed with a mean of 5.75 ounces and a standard deviation of 0.11 ounce. What percentage of the pucks ...
June 23, 2013 by david

Statistics
I'm going over some practice problems and I can't seem to figure this one out. Can anybody give me some help please? On a measure of artistic ability, the mean for college students in New Zealand is 150 and the standard deviation is 25. Give the Z scores for New Zealand ...
April 9, 2012 by Michael

statistics
In a sample of 100 steel wires the average breaking strength is 50 kN, with a standard deviation of 2 kN. a. Find a 95% confidence interval for the mean breaking strength of this type of wire. b. An engineer claims that the mean breaking strength is between 49.7 kN and 50.3 ...
October 29, 2011 by Don't get it!! :(

Stats
A random sample of dates taken from headstones at a cemetery in Pleasanton, California, showed an average lifespan of 70 years with a standard deviation of 20 years. Assuming the distribution is unimodal, which of the following is most likely a good description of the ...
October 9, 2011 by Anonymous

Statistics
The next three questions refer to the following situation. Data from previous years reveal that the distribution if first exam scores in an introductory statistics class is approximately normal with a mean of 72 and a standard deviation of 12. 16) Given that the passing score ...
August 24, 2013 by Tara

math- stat 201
A firm hires a pool of financial consultants to discuss portfolio recommendations with its clients. The CEO believes that another financial consultant should be hired if the average phone consultation exceeds 350 seconds. A random sample of 100 phone calls revealed a mean of ...
November 21, 2013 by lea

statistics
Suppose a manufacturer claims that each family-size bag of pretzels sold weighs 12 ounces on average with a standard deviation of 0.8 ounces. A consumer's group decides to test this claim. If a simple random sample of 49 bags of pretzels gives a sample mean of 11.8 ounces, is ...
February 25, 2014 by Ana

statistics
The number of accidents per week at a hazardous intersection varies with mean 2.2 and standard deviation 1.4. a. What is the distribution of Xbar, the mean number of accidents in one year, (52 weeks)? {Note you do not have to use R for this question, write down the ...
November 14, 2010 by cb

statistics
A basketball scout randomly selected 144 players and timed how long each player took to perform a certain drill. The times in this sample were distributed with a mean of 8 minutes. The population standard deviation was known to be 3 minutes. A. find the critical value for a 95...
April 27, 2014 by Mark

statistics/probability
QUESTION- machines are used to pack sugar into packets supposedly containing 1.20kg each.on testing a large number of packets over a long perodof time ,it was found that the mean weight of the packets was 1.24kg and the standard deviation was 0.04kg. a particular machine is ...
October 29, 2010 by sunil

statistics
A study was conducted in order to estimate μ, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard ...
June 26, 2013 by avery

statistics
A study was conducted in order to estimate μ, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard ...
June 26, 2013 by avery

statistics
A study was conducted in order to estimate μ, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard ...
June 26, 2013 by avery

statistics
A study was conducted in order to estimate μ, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard ...
June 26, 2013 by avery

statistics
Here are 6 measurements of the electrical conductivity of a iron rod: 10.08, 9.89,10.05,10.16,10.21,1011 The iron rod is supposed to have conductivity 10.1. Do the measurements give good evidence that the true conductivity is not 10.1? The 6 measurements are an SRS from the ...
November 5, 2012 by Anonymous

stats
Head lice can be a problem in classrooms. From the past experience, suppose it is predicted that 5% of the students will get lice if there are some reported cases. The health nurse checks 120 randomly chosen students and records the number of students that have head lice. ...
June 1, 2007 by Anonymous

Statistics
The weight of a small Starbucks coffee is a normally distributed random variable with a mean of 360 grams and a standard deviation of 9 grams. Find the weight that corresponds to each event. Show your work. a. Highest 10 percent; b. Highest 50 percent; c. highest 5 percent; d...
September 8, 2010 by Shon

statistics
Determine the sample size needed in order to be 95 percent confident the p, the sample proportion of HD television sets that last at least five years without a single repair, is within 0.03 of , the true proportion of sets that last at least five years without a single...
November 28, 2011 by Sierra

STATISTICS
A bank officer wants to determine the amount of the average total monthly deposits per customer at the bank. He believes an estimate of this average using a confidence interval is sufficient. a) How large a sample should he take to be within $200 of the actual average with 99...
November 21, 2010 by Jing Sun Q.

statistics
Entry to a certain University is determined by a national test. The scores on this test are normally distributed with a mean of 500 and a standard deviation of 100. Tom wants to be admitted to this university and he knows that he must score better than 70% of the students who ...
November 20, 2012 by Michelle

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