20. A business consultant wanted to investigate if providing day care facility on premises by companiesreduces the absentee rate of working mothers with 6-year old children. She took a sample of 45such mothers from companies that provide day care facilities on premises. These mothers missed anaverage of 6.4 days from work last year with a standard deviation of 1.20 days. Another sample of50 such mothers taken from companies that do not provide day care facilities on premises showedthat these mothers missed an average of 9.3 days last year with a standard deviation of 1.85 days.Construct a 98% confidence interval for the difference between the two population means.

Answered: 20. A business consultant wanted to…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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4. The strength of paper used by a certain company is approximately normally distributed with mean 30 p.s.i. and standard deviation 3 p.s.i. The company decides to test a new source of paper made by a different manufacturer. If this paper is significantly stronger, then the company will switch its trade to this new manufacturer. A batch of paper is
7) A tire manufacturer has been producing tires with an average life expectancy of 26,000 miles. Now the company is advertising that their new tires' life expectancy has increased. In order to test the legitimacy of their advertising campaign, an independent testing agency tested a sample of 85 of their tires. The agency found the mean of the 85 tires to be 27,000 miles and the standard deviation to be 3,970 miles. Use a 0.01 level of significance and test to determine whether the company is using legitimate advertising. (Show all seven steps.)
For a 4-unit class like Statistics, students should spend average of 12 hours studying for the class. A survey was done on 22 students, and the distribution of total study hours per week is bell-shaped with a mean of 12 hours and a standard deviation of 2.6 hours. Use the Empirical Rule to answer the following questions. a) 68% of the students spend between hours and hours on Statistics each week. b) 95% of the students spend between hours and hours on Statistics each week. c) 99.7% of the students spend between hours and hours on Statistics each week. Check Answer 100% 69°F Cloudy
34. A study was conducted to determine whether an expectant mother’s cigarette smoking has an effect on the bone mineral content of her otherwise healthy child. Particularly it was thought that smoking might lower the bone mineral content. To test this group 1 consisted of a sample of 77 newborns whose mothers smoked during pregnancy, their mean bone mineral content = 0.098 and the standard deviation = 0.026. Group 2 consisted of a sample of 161 infants whose mothers did not smoke during pregnancy, their mean = 0.095 and the standard deviation = 0.025. %3D %3D a) b) Are the two samples of data paired or independent? State the null and alternative hypothesis. (Do not do the test) buent Todousic a
4. Ashareholders' group, in lodging a protest, claimed that the mean tenure for a chief executive officer (CEO) was at least nine years. A survey of companies reported in The Wall Street Journal found a sample of 25 companies revealed a mean tenure of 7.27 years for CEOS with a sample standard deviation of 6.38 years. Use 1% significance level to test the claim that the mean tenure for a chief executive officer (CEO) was at least nine years.
Suppose that one-way commute times in a particular city are normally distributed with a mean of 25.16 minutes and a standard deviation of 1.45 minutes. Would it be unusual for a commute time to be above 21 minutes?
Suppose two food preservatives are extensively tested and determined safe for use in meats. A processor wants to compare the preservatives for their effects on retarding spoilage. Suppose 16 cuts of fresh meat are treated with preservative A with mean 95.25 and Sample standard deviation 13.45. And another 12 cuts of meat are treated with preservative B with mean 100.50 and standard deviation 10.55. The number of hours until spoilage begins is recorded for each of the 28 cuts of meat. The value of the test statistic for determining if there is a difference in the population variances for preservatives A and B is equal to: A. 1.129. OB. 1.275. OC. 1.625. OD. 0.784.
7. Tomorrow, Charlotte's athletic director will announce plans to start our very first Muggle Quidditch team, and you have been hired to do basic statistics for the fledgling team. Based on International Quidditch Association data, you know that winning scores for official games are normally distributed with a mean of 133.75 and a standard deviation of 50.24. a. In order to be invited to the college world cup, teams must earn a score in the top 15% of all scores. What is the score our team needs to beat in order to earn an invite? b. If 10 games are studied, about how many will have a winning score under 90 points?
10. The Bank of New England is concerned about the amount of debt being accrued by customers using its credit cards. The Board of directors decided to install an expensive monitoring system if the mean for all the bank’s customers is greater than $2000. The bank randomly selected 100 credit card holders and determined the amounts they charged. For this sample group the mean is $2190 and standard deviation is $760. Use 0.02 level of significance to test the claim that the mean amount charged is greater than $2000. Based on the results of testing, will the monitoring system be implemented?
After sitting in the waiting room for 12 minutes, a patient begins to complain. Is this patient’s wait time unusual?
For a 4-unit class like Statistics, students should spend average of 12 hours studying for the class. A survey was done on 30 students, and the distribution of total study hours per week is bell-shaped with a mean of 14 hours and a standard deviation of 2.7 hours. Use the Empirical Rule to answer the following questions. a) 68% of the students spend between hours and hours on Statistics each week. b) 95% of the students spend between hours and hours on Statistics each week. c) 99.7% of the students spend between hours and hours on Statistics each week.
Suppose that one-way commute times in a particular city are normally distributed with a mean of 15.94 minutes and a standard deviation of 1.232 minutes. Would it be unusual for a commute time to be above 20.2 minutes?

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