Wednesday
May 22, 2013

# Homework Help: Math: Statistics

Recent Homework Questions About Statistics

statistics
dole pineapple inc. is concerned that the 16 ounce cans are overfilled. assume the standard deviation is .03 onces. a random sample of 50 cans has a mean weight of 16.05 ounces. at the 5% level of significance can we conclude that the mean weight is > than 16 ounces. what ...
Monday, April 2, 2012 at 12:07am

statistics
If a spinner labeled 1-7 was spun 150 times, what is the probability of getting a prime number?
Sunday, April 1, 2012 at 9:30pm

Thaarugo, inc., produces a GPS device that is becoming popular in parts of scandinavia, When thaarugo produces one of these, a printed circuit board (PCB) is used, and it is populated with several electronic components, Thaarugo determines that it needs about 16,000 of this ...
Sunday, April 1, 2012 at 9:23pm

Statistics
At the Starlight Jewelry store, the customer preferences for wedding bands is 60% yellow gold, 29% white gold and 11% platinum. If 15 customers are randomly selected, what is the probability that more than 10 of them choose yellow gold wedding bands?
Sunday, April 1, 2012 at 5:22pm

statistics
If the grades on a police entrance exam are normally distributed with a mean of 100 and a standard deviation of 15, what percentage of students received grades of less than 115?
Sunday, April 1, 2012 at 2:04pm

statistics
A football coach claims that the average weight of all the opposing teams’ members is 225 pounds. For a test of the claim, a sample of 50 players is taken from all the opposing teams. The mean is found to be 230 pounds, and the standard deviation is 15 pounds. At a = 0.01...
Sunday, April 1, 2012 at 4:02am

statistics
transportation officials reported that 8.25 out every 1000 airline passengers lost luggage during their travels last year.if we randomly select 400 airline passengers,what is the probability that 5 lost some luggage?
Saturday, March 31, 2012 at 4:54am

statistics
Lost Luggage in Airlines Transportation officials reported that 8.25 out of every 1000 airline passengers lost luggage during their travels last year. If we randomly select 400 airline passengers, what is the probability that 5 lost some luggage?
Saturday, March 31, 2012 at 4:42am

statistics
A Packaging Company sells soda and claims each can contains 12 oz. A random sample of 15 sodas yielded a sample mean of 11.2 oz. Given the sample standard deviation is 0.3 oz, estimate the margin of error for a 90% confidence interval.
Thursday, March 29, 2012 at 10:15pm

statistics
A poll claims that 70% of the population is for a new amendment. A random sample of 49 people showed that 27 voted in favor of the new amendment. Give a 95% confidence interval. Give lower limit and upper limit accurate to four decimal places
Thursday, March 29, 2012 at 10:13pm

Statistics
if a rifleman averages 8 hits out of 10 shots at a target, what is the probability that he will hit the target in 3 out of 4 shots
Thursday, March 29, 2012 at 8:57pm

statistics
A study of 35 professors showed that the average time they spent creating test questions was 13.5 minutes per question. The standard deviation of the population is 3.8. Which of the following is the 99% confidence interval for the average number of minutes it takes to create a...
Thursday, March 29, 2012 at 6:32pm

statistics
According to a recent studey, 1 in every 4 women has been a victim of domestic abuse at some point in her life. Suppose we have randomly and independently sampled twenty-five women and asked each whether she has been a victim of domestic avbuse at some point in her life. Fidn ...
Thursday, March 29, 2012 at 3:13pm

Statistics
A recent survey found that 72% of all adults over 50 wear glasses for driving. In a random sample of 100 adults over 50, what is the mean and standard deviation of the numbe who wear glasses?
Thursday, March 29, 2012 at 3:09pm

Statistics
Give a brief account of the chief methods of collecting primary data? My answer: is personal Investigation Through investigation collection through questionnaire and through telephone, and of course i have explained each one of them, i just wanted whether what i have written ...
Thursday, March 29, 2012 at 12:58pm

statistics
Your customer is using a 620R to deliver fluid to a 25 liter bottle. He calls you and says the delivery rate has a lot of pulsation at the delivery pressure he is operating. If the bottles are not seated exactly in the holder, which happens often the first pulse of fluid from ...
Wednesday, March 28, 2012 at 8:01pm

Statistics
A window is shaped like a rectangle whose perimeter is 400 inches the length is 7 times as long as the width find the length and the width?
Wednesday, March 28, 2012 at 12:50am

Statistics
A machine is used to fill soda bottles in a factory. The bottles are labeled as containing 2.0 liters, but extra room at the top of the bottle allows for a maximum of 2.25 liters of soda before the bottle overflows. The standard deviation of the amount of soda put into the ...
Tuesday, March 27, 2012 at 10:40pm

statistics
Assume that a sample is used to estimate a population proportion p. Find the margin of error. 95% confidence; n = 250, x = 130
Tuesday, March 27, 2012 at 9:37pm

statistics
The time it takes Jessica to bicycle to school is normally distributed with an average of a third of an hour and a variance of 9 minutes. Jessica has to be at school at 8:15 am. What time should she leave the house so she will be late on 5% of the time?
Tuesday, March 27, 2012 at 8:53pm

statistics
Suppose that SAT scores among U.S. college students are normally distributed with a mean of 450 and a standard deviation of 150. What is the probability that a randomly selected individual from this population has an SAT score at or below 600?
Tuesday, March 27, 2012 at 6:44pm

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
Tuesday, March 27, 2012 at 6:43pm

statistics
At a local high school students were randomly assigned to one of two math teachers- Mrs smith and mrs jones. After the assignment, Mrs Smith had 30 students and mrs jones had 25 students. at the end of the year each class took the same standardized test. mrs smiths students ...
Tuesday, March 27, 2012 at 2:50pm

Statistcs
Assume that a ramdom sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confinence level. n=550, x=165, 95% confindence
Tuesday, March 27, 2012 at 2:14pm

statistics
The Medical Rehabilitation Foundation reports that the average cost of rehabilitation for stroke victims is at least \$24,500. To see if the average cost might be different at a particular hospital, a researcher selects a random number sample of 50 stroke victims and finds that...
Tuesday, March 27, 2012 at 1:59pm

statistics
Mail security estimates that the average daily per-store theft is less than \$250, but wants to determine accuracy of this statistic. The company researcher takes a sample of 81 clerks and finds that X =\$260 and s=\$20. a) Test at a=.05 b) Construct a 95% CIE of u
Tuesday, March 27, 2012 at 1:55pm

statistics
Mail security estimates that the average daily per-store theft is less than \$250, but wants to determine accuracy of this statistic. The company researcher takes a sample of 81 clerks and finds that X =\$260 and s=\$20. a) Test at a=.05 b) Construct a 95% CIE of u
Tuesday, March 27, 2012 at 1:52pm

Statistics
Find the probability P(E or F) if E and F are mutually exclusive and P(E)=0.30 and P(F) =0.47
Tuesday, March 27, 2012 at 1:14pm

managerial statistics
student conduct a study and reported that 95% confidence intervak for themean ranged from 46-54. He was surethat the mean of the sample was 50,that the standard deviation of the sample was 16and that the sample was atleast 30 but could not remember exact number. can you help me
Tuesday, March 27, 2012 at 9:51am

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&#...
Monday, March 26, 2012 at 9:15pm

statistics
the dean of admissions in a large university has determined that the scores of the freshman class in a mathematics test are normally distributed with a mean of 86 and a standard deviation of 11. A sample of 50 students is selected at random from the entire freshman class. ...
Monday, March 26, 2012 at 7:56pm

Psychology Statistics
Not sure how to rewrite this question: ht tp://img221. imageshack.us/ img221/601/question2. jpg Get rid of all the spaces to see image of question.
Monday, March 26, 2012 at 5:54pm

Statistics Psychology
I'm confused about how to prove this question: ht tp://imageshack.us/ photo/my-images/708/ question1c. jpg/ Get rid of all the spaces
Monday, March 26, 2012 at 5:49pm

statistics
(Quiz 240 ) Stratified Sampling: The owner of a private food store is concerned about employee morale. She decides to survey the mangers and hourly employees to see if she can learn about work environment and job satisfaction. From the list of workers at the store, obtain a ...
Monday, March 26, 2012 at 2:18pm

statistics
1. The fracture strength of a certain type of manufactured glass is normally distributed with a mean of 579 MPa with a standard deviation of 14 MPa. (a) What is the probability that a randomly chosen sample of glass will break at less than 579 MPa? (b) More than 590 MPa? (c) ...
Monday, March 26, 2012 at 1:09pm

statistics
I need an example of constructing a frequency polygon and have never used excel. I know what I'm supposed to put on the graph, I just don't know how to construct one on a computer.
Monday, March 26, 2012 at 5:12am

Statistics
A social psychologist asked 15 college students how many times they "fell in love" before they were 11 years old. The numbers of times were as follows: 2,0,6,0,3,1,0,4,9,0,5,6,1,0,2 make (a) a frequency table and (b) a histogram. Then describe the general shape of ...
Monday, March 26, 2012 at 1:07am

Statistics
I am having trouble with this problem. A participant in a cognitive psychology study is given 50 words to remember and later asked to recall as many as he can of them. This participant recalls 17. What is the (a)variable, (b)) possible values, and (c) score? is this correct? ...
Monday, March 26, 2012 at 1:02am

statistics
7. A recent study investigated the effects of a "Buckle Up Your Toddlers" campaign to get parents to use the grocery cart seat belts. When gathering baseline data prior to the campaign, investigators observed 86 out of 640 parents buckling up their toddlers. Assume ...
Monday, March 26, 2012 at 12:52am

statistics
A random sample of the houses in a particular city is selected and the level of radon gas is measured for each house in the sample. The values collected are given below in parts per million (ppm). Experience has shown that radon gas level is approximately normally distributed ...
Monday, March 26, 2012 at 12:50am

statistics
One method for estimating the availability of office space in large cities is to conduct a random sample of offices, and calculate the proportion of offices currently being used. Suppose that real estate agents believe that of all offices are currently occupied, and decide to ...
Monday, March 26, 2012 at 12:50am

statistics
According to internal testing done by the Get-A-Grip tire company, the mean lifetime of tires sold on new cars is 23,000 miles, with a standard deviation of 2500 miles. a) If the claim by Get-A-Grip is true, what is the mean of the sampling distribution of for samples of size...
Monday, March 26, 2012 at 12:49am

statistics
In a study of termite populations in Swaziland, the following data were gathered on the percentage of termites that were classified as "major workers" at seven randomly selected sites:37.6 20.0 28.8 29.9 51.9 13.6 34.5 29.0 a)Use the given data to produce a point ...
Monday, March 26, 2012 at 12:48am

statistics
A person can order a new car with a choice of 9 possible colors, with or without ac, with or without heated seats, with it without anti lock breaks, with or without power windows and with or without a CD player. How many different ways can a new car be ordered with these ...
Sunday, March 25, 2012 at 6:47pm

statistics
The number of pizzas consumed per month by university students is normally distributed with a mean of 9 and a standard deviation of 5. What is the probability that in a random sample of size 10, a total of more than 80 pizzas are consumed? (Hint: What is the mean number of ...
Sunday, March 25, 2012 at 4:18pm

statistics
Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?
Sunday, March 25, 2012 at 3:37am

Statistics
Long term experience showed that after a type of eye surgery, recovery time has a mean of u = 5.3 days in a hospital. A random sample of 40 patients, with this type of eye surgery, were treated as outpatients during recovery and the sample mean recovery time was 4.2 days. Does...
Sunday, March 25, 2012 at 2:55am

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 ...
Sunday, March 25, 2012 at 2:47am

Statistics
How long does it take to have food delivered? A Chinese restaurant advertises that the mean delivery will be no more than 30` minutes. A random sample of delivery times is shown below. Based on this sample data, is the mean delivery time different than 30 minutes? Use a 5% ...
Sunday, March 25, 2012 at 2:44am

Statistics
A large furniture store has begun a new ad campaign on local television. Before the campaign, the long term mean daily sales were \$24,819. A random sample of 40 days during the new ad campaign gave a sample mean daily sale of \$25,910. Does this indicate that the population ...
Sunday, March 25, 2012 at 2:40am

Statistics
Computer Depot is a large store that sells and repairs computers. A random sample of 110 computer repair jobs took technicians an average of 93.2 minutes per computer. Assume that o is known to be 16.9 minutes. Find a 99% confidence interval for the population mean u for the ...
Sunday, March 25, 2012 at 2:38am

Statistics
Mr. Crandall has assigned a term paper due at the end of the semester. He would like to know the average length of the papers. The data below are the he numbers of types pages from a random sample of 10 term papers. Use these data to compute a 95% confidence interval for the ...
Sunday, March 25, 2012 at 2:36am

Statistics
A random sample of 14 evenings at the O'Sullivan house hold showed that the family received an average of 2.4 solicitation calls each evening. The sample standard deviation was s= 0.9. Find a 99% confidence interval for the population mean number of solicitation calls this...
Sunday, March 25, 2012 at 2:33am

Statistics
A study is being planned to estimate the mean number of semester hours taken by students at a college. The population standard deviation is assumed to be o=4.7 hours. How many students should be included in the sample to be 99% confident that the sample mean is within one ...
Sunday, March 25, 2012 at 2:31am

Statistics
Which of these statements is not true about the variance in a binomial distribution B(n, p)? __________ A. For a fixed p, the variance increases as n increases. B. For a fixed n, the variance is maximum when p = 0.5. C. The variance depends only on n. D. The variance is ...
Saturday, March 24, 2012 at 4:00pm

statistics
The data was obtained from car crash experiments. The table values are the chest deceleration data (g) for the dummy in the driver’s seat. Use a 0.05 significance level to test the null hypothesis that the different weight categories have the same mean. Do the data ...
Saturday, March 24, 2012 at 1:07pm

statistics
The data set given below has y^ = 3x - 5 for its regression equation. Find the standard error of estimate. x 3 2 5 8 y 4 1 10 19 A) 1.29 B) 0 C) 2.06 D) 0.17
Friday, March 23, 2012 at 6:17pm

statistics
Let U, V be random numbers chosen independently from the interval [0; 1] with uniform distribution. Find the cumulative distribution and density of each of the variables (a) Y = U + V. (b) Y = Absolute value of (U - V).
Friday, March 23, 2012 at 2:06pm

statistics
What are the chances that a person who is murdered actually knew the murderer? About 64% of people who are murdered actually knew the murderer. Suppose that a detective file in New Orleans has 63 unsolved murders. What is the probability that A )at least 35 of the victims knew...
Friday, March 23, 2012 at 12:01pm

statistics
At a small college it is known from previous years that 35% of all college freshman start in college algebra. The new freshman class has 100 students in it, What is the probability that between 35 and 42 freshman will start in college algebra? Is it reasonable to approximate ...
Friday, March 23, 2012 at 11:36am

statistics
A fast food chain claims that all of its quick win soda cups are winners. (There is a little tab you pull off the side of the cup which says either you are a winner or not. Lisa bought 8 sodas to try her luck. What is the probability that at least 5cups were winners? What is ...
Friday, March 23, 2012 at 11:34am

statistics
The Denver Post stated that 80% of all new products introduced in grocery stores fail (are taken off the market) within 2 years. If a grocery chain introduces 66 new products, what is the probability that within 2 years , 7 or more fail? What is the probability that within 2 ...
Friday, March 23, 2012 at 11:33am

Statistics
team members estimated that a group of participants spent an average of \$90.00 with a standard deviation of \$15.00. What is the maximum amount that you can spend and still be in the lowest 20%? and the minimum that you need to be in the highest 15%?
Friday, March 23, 2012 at 10:01am

statistics
In class of 125 students, 70 students passed in Math, 56 students passed in Statistics, and 30 passed in both. The probability that a student selected at random from the class, has passed in only one subject is
Thursday, March 22, 2012 at 10:09pm

Statistics Question
For a test of Ho: p = 0.5, the z test statistic equals 1.52. Find the p-value for Ha: p > 0.5.
Thursday, March 22, 2012 at 9:37pm

Statistics
If a researcher were studying the effects of a teaching method on patient learning outcomes, how would the research question need to be worded to use a t-test to test for statistical differences? What would the null and alternative hypotheses be?
Thursday, March 22, 2012 at 9:14pm

types of businesss writing
My third piece. Draft an email of at least four complete sentences to Deb Walker, the designated trainer: A. Confirm the arrangements for the seminar providing only the information she needs to arrive at the right place at the right time. B. copy both Mr. Dittmer and Ms. ...
Thursday, March 22, 2012 at 8:59pm

statistics
If a student takes an exam containing 12 true or false questions. If the student guesses what is the probability that he will get exactly 8 questions right?
Thursday, March 22, 2012 at 7:59pm

Basic Statistics
Historically, the proportion of adults over the age of 24 who smoke has been estimated to be .30. You want to take a sample to estimate the current proportion of adults over the age of 24 who smoke within 3% at 95% accuracy. When you completed the sample you found that 114 of ...
Thursday, March 22, 2012 at 3:07pm

statistics
Calculate the z-score for each set of data. Determine who did better on her respective test, Tonya or Lisa. Student English Test Grade z-Score Student Math Test Grade z-Score John 82 Jim 81 Julie 88 Jordan 85 Samuel 90 Saye 79 Tonya 86 Lisa 82 Mean 86.50 81.75 St. Dev. 3.42 2...
Thursday, March 22, 2012 at 3:03pm

statistics
A random sample of 36 statistics students were asked to add a column of numbers. The amount of time required to compute the sum was recorded for each student. The sample mean time was 54 seconds with a sample standard deviation of 18 seconds. 1. Construct a 95% confidence ...
Thursday, March 22, 2012 at 1:09pm

statistics
in a class of 28 students, each student has a 90% chance of attending any given class and student act independently. what is the probability that tomorrow's class has perfect attendance?
Thursday, March 22, 2012 at 12:41pm

statistics
a random variable having a normal distribution with σ = 0.05 ounce, find the mean such that only 1% of the bags contain less than 8 ounces of potato chips.
Thursday, March 22, 2012 at 12:17pm

statistics
The actual amount of potato chips that a filling machine puts into an “8-ounce” bag varies from bag to bag. If we consider the amount put into each bag as a random variable having a normal distribution with σ = 0.05 ounce, find the mean such that only 1% of the ...
Thursday, March 22, 2012 at 12:13pm

statistics
Rootover 5.3 in number line
Thursday, March 22, 2012 at 11:55am

statistics
At the end of the festival the organizers estimated that a family of participants spent an average of \$90.00 with a standard deviation of \$15.00. What’s the probability that the mean amount spent will be NO more than \$75?
Wednesday, March 21, 2012 at 8:53pm

Statistics
With a spent average of \$90.00 with a standard deviation of \$15.00, what is the maximum amount that you can spend and still be in the lowest 20%?
Wednesday, March 21, 2012 at 7:26pm

math
Statistics: Analyze student exam scores Students were given an exam with 300 multiple choice questions. The distribution of the scores were normal and the mean was 195 with a standard deviation of 30. you may find it helpful to draw out this distribution before answering the ...
Wednesday, March 21, 2012 at 6:01pm

statistics
we need to estimate the percentage of businesses that plan to hire additional employees in the next 60 days. How many randomly selected employers must we contact in order to create an extimate in which we are 98% confident , with an error of 5%
Wednesday, March 21, 2012 at 5:12pm

statistics
1-the graduate selection committee wants to select the top 10% of applicants. On a standardized test with a mean of 500 and a standard diviation of 100, what would be the cutoff score for selecting the top 10% of applicants, assuming that test is normally distributed?
Wednesday, March 21, 2012 at 4:24pm

statistics
Musical styles other than rock and pop are becoming more popular. A survey of college students finds that 48% like country music, 30% like gospel music, and 10% like both. What is the conditional probability (±0.01) that a student likes gospel music, given that he or ...
Wednesday, March 21, 2012 at 12:36pm

statistics
in a batch of 15 students failed in a test. the marks of 10 who have passed were 9,6,7,8,8,9,6,5,4,7.find the median of all 15 students.
Wednesday, March 21, 2012 at 12:11pm

statistics
Late payment of medical claims can add to the cost of health care. An article (M. Freudenheim, "The Check Is Not in the Mail," The New York Times, May 25, 2006, pp. C1, C6) reported that for one insurance company, 85.1% of the claims were paid in full when first ...
Wednesday, March 21, 2012 at 11:32am

Statistics
Suppose that the travel time from your home to your office is normally distributed with a mean of 40 minutes and standard deviation of 7 minutes. If you want to be 95% certain that you will not be late for an office appointment at 1:00pm, what is the latest time that you ...
Tuesday, March 20, 2012 at 10:26pm

statistics
The average score on a science test was 72 with a standard deviation of 6. The average score on a history test was 89 with a standard deviation of 7. Compare the variability of the two classes.
Tuesday, March 20, 2012 at 8:44pm

statistics
The scores on a national achievement test are normally distributed with a mean of 50 and a standard deviation of 10. Out of a group of 200 students, how many would you expect to score more than 70?
Tuesday, March 20, 2012 at 8:07pm

statistics
Consider a random sample of 37 students, and consider the number who graduate in six years. . Find the probability that 20 students in the sample graduate in six years
Tuesday, March 20, 2012 at 4:57pm

statistics
The distribution of scores is normal with a ì = 100 and ó =15. What proportion of the population have scores A) Above 130? B) Below 90? C) Above 110?
Tuesday, March 20, 2012 at 3:09pm

statistics
from generation to generation, the average age when smokers first start to smoke caties. however, the standatd deviation of that age remains constant of around 2.1 years. a survey of 40 smokers of this generation was done to see if the average starting age is at least 19. the ...
Tuesday, March 20, 2012 at 1:58pm

statistics
customer arrive at alocal ice cream stand at an average rate of 16 perhour. what is the probability that 2 customer will arrive during the next 15 minutes?
Tuesday, March 20, 2012 at 1:19pm

statistics
Bill spends an average of 5 minutes each day waiting in lines. If Bill is typical of the 290 million people in the United States, which of the following expresses the approximate combined amount of time these people spend annually waiting in line? A. 1.45 × 109 minutes a...
Tuesday, March 20, 2012 at 1:12pm

Statistics
The home states of a certain group of people are distributed as follows: 53 percent are from MISSOURI, 21 percent are from KANSAS, and 26 percent are from IOWA. (No one in the group had a home state other than one of these three.) (Note: Your answer to the question below ...
Tuesday, March 20, 2012 at 3:20am

STATISTICS
Suppose that, for students who are enrolled in college algebra, 78 percent are freshmen, 40 percent are female, and 28 percent are female and are freshmen. Your answers below should be entered as decimals and rounded to three decimal places. (a) One student will be selected at...
Monday, March 19, 2012 at 10:28pm

statistics
writing to explain. the median score on a test is 90. is it possible to add two more scores to the data and still have a median score of 90? explain ypur answer
Monday, March 19, 2012 at 10:15pm

statistics
An expert witness in a case of alleged racial discrimination in a state university school of nursing introduced a regression of the determinants of Salary of each professor for each year during an 8-year period (n = 423) with the following results, with dependent variable Year...
Monday, March 19, 2012 at 9:11pm

statistics
(a) Plot the data on lightning deaths. (b) Describe the trend (if any) and discuss possible causes. (c) Fit an exponential trend to the data. Interpret the fitted equation. (d) Make a forecast for 2005, using a trend model of your choice (or a judgment forecast). Explain the ...
Monday, March 19, 2012 at 9:08pm

statistics
if the class limit is 11-20 and the class boundary is 10.5-20.5,what is the class width?
Monday, March 19, 2012 at 5:38pm

statistics
Suppose that, for students who are enrolled in college algebra, 73 percent are freshmen, 48 percent are female, and 31 percent are female and are freshmen. Your answers below should be entered as decimals and rounded to three decimal places. Two students will be independently ...
Monday, March 19, 2012 at 2:15pm

statistics
Show the work for 750 x 23%, how do you do it?
Monday, March 19, 2012 at 9:59am

Statistics
John runs a computer software store. Yesterday he counted 127 people whwo walked by his store, 58 of whom came into the store. OF the 58, only 25 bought something in the store. A. What is probability that a person who walks by the store will enter the store? B. What is the ...
Monday, March 19, 2012 at 1:40am

statistics
A sample of 352 subscribers to Wired magazine shows the mean time spent using the Internet is 13.4 hours per week, with a sample standard deviation of 6.8 hours. Find the 95 percent confidence interval for the mean time Wired subscribers spend on the Internet.
Monday, March 19, 2012 at 12:50am

statistics
Four research participants take a test of manual dexterity (high scores mean better dexterity) and an anxiety test (high scores mean more anxiety). The scores are as follows. Person Dexterity Anxiety 1 1 10 2 1 8 3 2 4 4 4 –2
Sunday, March 18, 2012 at 11:27pm

statistics
A student is interested in whether students who study with music playing devote as much attention to their studies as do students who study under quiet conditions (he believes that studying under quiet conditions leads to better attention). he randomly assigns participants to ...
Sunday, March 18, 2012 at 4:39pm

Introduction to statistics
A vending machine dispenses coffee into an eight-ounce cup. The amount of coffee dispensed into the cup is normally distributed with a standard deviation of .03 ounce. You can allow the cup to OVERFILL 1% of the time. What amount should you set as the mean amount of coffee to ...
Sunday, March 18, 2012 at 4:19pm

statistics
Times for a surgical procedure are normally distributed. Method A has a mean of 28 minutes and a standard deviation of 2 minutes for completion. What is the probability that a surgical procedure conducted by method A takes at most 33 minutes to complete?
Saturday, March 17, 2012 at 9:49pm

statistics
The mean life of a set of batteries in a T83 calculator is 525 with a standard deviation of 35 hours assume normal distribution is normal whats is the probability that set will last for more the 540 hrs
Saturday, March 17, 2012 at 7:15pm

statistics
The Acme Car Company claims that at most 8% of its new cars have a manufacturing defect. A quality control inspector randomly selects 300 new cars and finds that 33 have a defect. Should she reject the 8% claim? Assume that the significance level is 0.05.
Saturday, March 17, 2012 at 12:13am

statistics
mean=80 v=40
Friday, March 16, 2012 at 6:03pm

statistics
create a survey results that have a sample proportion of 23%
Friday, March 16, 2012 at 5:30pm

statistics
the average temp of the lake is 64.2 degrees and the standard deviation is 3.2. Assume the cariable is normally distributed. For a randomly selected day find the probabliity that the temp will be above 62 degrees
Friday, March 16, 2012 at 4:18pm

statistics
it has been reported that 40% of all internet users have been attacked by viruses. If 20 people are randomly surveyed, find the following probabilities: a. At least 3 have been attacked b. No more than 5 have been attacked c. less than 15 have been attacked
Friday, March 16, 2012 at 1:57pm

statistics
If you want to be 95% confident of estimating the population proportion to within a sampling error of and there is historical evidence that the population proportion is approximately 0.40, what sample size is needed?
Friday, March 16, 2012 at 1:04pm

statistics
(a) Plot the data on lightning deaths. (b) Describe the trend (if any) and discuss possible causes. (c) Fit an exponential trend to the data. Interpret the fitted equation. (d) Make a forecast for 2005, using a trend model of your choice (or a judgment forecast). Explain the ...
Thursday, March 15, 2012 at 11:05pm

statistics
An expert witness in a case of alleged racial discrimination in a state university school of nursing introduced a regression of the determinants of Salary of each professor for each year during an 8-year period (n = 423) with the following results, with dependent variable Year...
Thursday, March 15, 2012 at 10:56pm

statistics
In the following regression, X = total assets (\$ billions), Y = total revenue (\$ billions), and n = 64 large banks. (a) Write the fitted regression equation. (b) State the degrees of freedom for a twotailed test for zero slope, and use Appendix D to find the critical value at...
Thursday, March 15, 2012 at 10:48pm

Statistics
sd 20 mean 100 x 125 looking at table z-0.8944 do we put a 1 in front and substract it from 0.8944 to make it .1056 or is the answer just the number the table indicates? In other words does the problem finish after you get the z number or do we continue by putting the #1
Thursday, March 15, 2012 at 9:38pm

statistics
Suppose that people's heights (in centimeters) are normally distributed, with a mean of 165 and a standard deviation of 6. We find the heights of 80 people. (a) How many would you expect to be between 158 and 172 cm tall?
Thursday, March 15, 2012 at 9:19pm

statistics
10.51 A statistics professor compared the scores of her morning class and afternoon class on the same quiz. The 42 morning students’ average score was 83.52 with a standard deviation of 7.81, while the 46 afternoon students’ average score was 79.44 with a standard ...
Thursday, March 15, 2012 at 8:44pm

Statistics
A coffee company wants to make sure that there coffee is being served at the right temperature. If it is too hot, the customers could burn themselves. If it is too cold, the customers will be unsatisfied. The company has determined that they want the average coffee temperature...
Thursday, March 15, 2012 at 5:18pm

Statistics
4. A coil of wire has 600 metres of wire. Suppose there are 20 nicks (the most common problem with wire) are randomly distributed on a coil. a) What is the probability that in a 60 metre length of wire there will be at least 3 nicks? b) What is the probability that in a 47 ...
Thursday, March 15, 2012 at 2:48pm

statistics
assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 20. find the probability that a randomly selected adult has an IQ less than 20.
Wednesday, March 14, 2012 at 5:33pm

statistics
a statistics professor plans classes so carefully that the lenghts of her classes are uniformly distributed between 46.0 and 56.0 minutes. find the probability that a given class period runs less than 50.5 minutes
Wednesday, March 14, 2012 at 5:09pm

Statistics!
I'm doing an assignment about choosing the best promotion by analysing some sets of data that have been provided for us. Other then the mean, what would be the most effective measure to use?
Wednesday, March 14, 2012 at 12:40pm

Statistics
Hi, Ive looked online and in my textbook but I cant a good explanation. Basically, I need a detailed explanation of why quartile deviation is very effective?
Wednesday, March 14, 2012 at 12:31pm

Statistics Question (Confidence Interval)
A sample of 15 recent college graduates found that starting salaries for attorneys in New York City had a mean of \$102,342 and a standard deviation of \$21,756. Construct a 95% confidence interval for the average starting salary of all attorneys in the city. A. (89869.82, ...
Wednesday, March 14, 2012 at 11:15am

Statistics
suppose a random sample of 360 students is drawn form a population of students. Among sampled, the average IQ score is 12 with standard deviation of 3. What is the upper confidence limit of the 95% confidence interval of the population
Wednesday, March 14, 2012 at 3:18am

Statistics
Suppose that people's heights (in centimeters) are normally distributed, with a mean of 165 and a standard deviation of 6. We find the heights of 100 people. (a) How many would you expect to be between 157 and 173 cm tall? (b) How many would you expect to be taller than ...
Wednesday, March 14, 2012 at 12:22am

statistics
52 cards, where you randomly pull cards from the deck and record what they are, you find that over 1000 random draws, you pull an ACE 76 times. What would be the calculated probability based on relative frequency?
Tuesday, March 13, 2012 at 11:00pm

statistics
Choose either 2 ¡Á 2 contingency table shown below (males or females). Research question: At ¦Á = .005, is smoking independent of race? (Smoking rates are from Statistical Abstract of the United States, 2001, pp. 16 and 12, applied to hypothetical ...
Tuesday, March 13, 2012 at 10:36pm

statistics
A study of health care planning undertook a mail survey of hospital administrators in Arkansas, Louisiana, and east Texas. Research question: At á = .05, is the type of planning independent of the intensity of competition? (Data are from D. O. McKee, P. R. Varadarajan, ...
Tuesday, March 13, 2012 at 10:34pm

statistics
Get an answer from tutors to this homework question now:have to: (a) Write the claim mathematically and identify H0 and Ha (b) Find the standardized test statistic Z and its corresponding area. (c) Find the P-value. (d) Decide whether to reject or fail to reject the null ...
Tuesday, March 13, 2012 at 10:25pm

statistics
if the mean of a test score is 30 and the standard deviation is 3.7. which score could be expected to occur the least often?
Monday, March 12, 2012 at 9:38pm

Statistics
Quick question, can an obtained value be negative?
Monday, March 12, 2012 at 8:32pm

Statistics
The distribution of scores on a test is mound-shaped and symmetric with a mean score of 78. If 68% of the scores fall between 72 and 84, which of the following is most likely to be the standard deviation of the distribution? 3, 1, 4, 6?
Monday, March 12, 2012 at 5:15pm

statistics
The Sledge Tire and Rubber Company plans to warranty its new mountain bike tire for 12 months. However, before it does this, the company wants to be sure that the mean lifetime of the tires is at least 18 months under normal operations. It will put the warranty in place unless...
Monday, March 12, 2012 at 3:42pm

statistics
in an effort to increase production of an automobile part, the factory manager decides to play music in the manufacturing area. Eight workers are selected, and the number if items each produced for a specfic day is recored. After one week of music, the same workers are ...
Monday, March 12, 2012 at 12:56pm

statistics
Fit a regression line = a+bXi by the method of Least squares to the given sample information. Observations 1 2 3 4 5 6 7 8 9 10 Income (X)(’00 Rs) Consumption Expenditure(Y)(’00 Rs) 10 44 5 60 25 39 37 51 96 80 94 70 110 80 30 30 79 50 65 40
Monday, March 12, 2012 at 4:21am

statistics
16. Based on tests of the Chevrolet Cobalt, engineers have found that the miles per gallon in highway driving are normally distributed, with a mean of 32 miles per gallon and a standard deviation 3.5 miles per gallon
Saturday, March 10, 2012 at 10:14pm

statistics
if the average number of textbooks in professors' offices is 16, the standard deviation is 5, and the average age of the professors is 43,with a standard deviation of 8 ,which data set is more variable ?
Saturday, March 10, 2012 at 6:11pm

Statistics
Let x and y be the amounts of time (in minutes) that a particular commuter must wait for a train on two independently selected days. Define a new random variable w by w = x + y, the sum of the two waiting times. The set of possible values for w is the interval from 0 to 2a (...
Saturday, March 10, 2012 at 4:30pm

statistics
1. A test has a mean of 50, standard deviation of 10. A. What scores separate the middle 25% from the rest b. What proportion would be expected to score between 45 and 55 c. What proportion would be expected to score 68 and above
Saturday, March 10, 2012 at 3:21pm

statistics
Just wondering if someone is able to give instructions as to how to go about this questions? As part of a large research project, a social psychologist develops a measure of global environmental attitudes (i.e., general attitudes towards the environment). Scores on this ...
Saturday, March 10, 2012 at 1:49pm

statistics
M= 19.8 SD= 7.2 What is the probability of randomly selecting a student with a treadmill time greater than 25 minutes? In symbols, P(X > 25) = ?
Saturday, March 10, 2012 at 1:24pm

statistics
M= 500 SD= 100 What X value, separates the top 15% of the distribution from the rest?
Saturday, March 10, 2012 at 1:06pm

statistics
1. On a measure of anxiety, the mean is 79 and the standard deviation is 12. What are the z-scores for each of the following raw scores?
Saturday, March 10, 2012 at 12:54pm

statistics
A biologist estimates that 80% of the deer in a region carry a certain type of tick. For a sample of 300 deer selected at random what is the chance that 246 or fewer deer have this tick?
Friday, March 9, 2012 at 9:49pm

statistics
A score that is 6 points below the mean corresponds to a z-score of z= - .50, what is the population standard deviation?
Friday, March 9, 2012 at 3:28pm

statistics
In a population of exam scores,a score of X= 48 corresponds to z= 1 and a score of X= 36 corresponds to z= -.50. Find the mean and standard deviation for the population?
Friday, March 9, 2012 at 3:23pm

statistics
The time required by workers to complete an assembly job has a mean of 50 minutes and a standard deviation of 8 minutes. To spot check the workers' progress on a particular day, their supervisor intends to record the times 60 workers take to complete one assembly job ...
Thursday, March 8, 2012 at 5:46pm

statistics
A random sample of 31 people employed by the Florida state authority established they earned an average wage (including benefits) of \$56 per hour. The sample standard deviation was \$6.35 per hour. (a)What is your best estimate of the population mean? (b)Develop a 99 percent ...
Thursday, March 8, 2012 at 5:18pm

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