gMAT 305 Week 4 homework

Exercise 9-23

 A survey is being planned to determine the mean amount of time corporation executives watch television. A pilot survey indicated that the mean time per week is 13 hours, with a standard deviation of 3.0 hours. It is desired to estimate the mean viewing time within one-quarter hour. The 95 percent level of confidence is to be used.

How many executives should be surveyed? (Round up your answer to the next whole number.)  

Exercise 9-42

 An important factor in selling a residential property is the number of people who look through the home. A sample of 15 homes recently sold in the Buffalo, New York, area revealed the mean number looking through each home was 24 and the standard deviation of the sample was 5 people.

Develop a 95 percent confidence interval for the population mean. (Round your answers to 2 decimal places.)

Confidence interval for the population mean is between and ? 

Exercise 9-47

 As a condition of employment, Fashion Industries applicants must pass a drug test. Of the last 440 applicants 22 employees failed the test. 

Develop a 95% confidence interval for the proportion of employees that fail the test. For the random tests conducted, the confidence interval is    and  

Would it be reasonable to conclude that less than 4 percent of the employees are not able are not able to pass the random drug test? 

Exercise 9-28

Forty-nine items are randomly selected from a population of 500 items. The sample mean is 40 and the sample standard deviation 9. 

Develop a 99 percent confidence interval for the population mean? (Round your answers to 3 decimal places . 

The confidence interval is between   and  

Exercise 9-28

For a given confidence interval, what is the interpretation of a 96% confidence level? 

A) 96% chance that the given interval includes the true value of the population parameter 

B) Approximately 96 out of 100 such intervals would include the true value of the population parameter 

C) 4% chance that the given interval does not include the true value of the population parameter 

D) Both "a" and "c" are true 

Exercise 10-2

  

The following information is available. 

  

H0:   µ ≥ 26
  H1: µ < 26 

The sample mean is 28, for a sample size of 48. The population standard deviation is 4. Use the .05 significance level.

Exercise 10-63

The following null and alternate hypothesis are given.

H0: µ ≥ 50

 H1: µ > 50 

 Suppose the population standard deviation is 10. The probability of a Type 1 eror is set at .01 and the probability of a Type 11 error at .30. Assume that the population mean shifts from 50 to 55. How large a sample is necessary to meet these requirements? (Round your answer to the nearest whole number).

Exercise

 According to a study by the American Pet Food Dealers Association, 49 percent of U.S. households own pets. A report is being prepared for an editorial in the San Francisco Chronicle. As a part of the editorial a random sample of 325 households showed 210 own pets. Does this data disagree with the Pet Food Dealers Association data? Use a 0.20 level of significance. 

 

A. State the null hypothesis and the alternate hypothesis.

B. State the decision rule for 0.20 significance level.

C. Compute the value of the test statistic.

D.Does this data disagree with the Pet Food Dealers Association data? Use a 0.20 level of significance.

Exercise

14. What is the probability of making a Type 11 error if the null hypothesis is actually true