Exam 10: Two-Sample Tests

The Wall Street Journal recently ran an article indicating differences in perception of sexual Harassment on the job between men and women.The article claimed that women perceived the Problem to be much more prevalent than did men.One question asked to both men and women Was: "Do you think sexual harassment is a major problem in the American workplace?" Some 24% of the men compared to 62% of the women responded "Yes." Suppose that 150 women and 200 men were interviewed.What conclusion should be reached?

SCENARIO 10-3 -Referring to Scenario 10-3, suppose = 0.10.Which of the following represents the correct Conclusion?

SCENARIO 10-5 10-16 Two-Sample Tests -Referring to Scenario 10-5, what is the critical value for testing at the 5% level of significance Whether the business school preparation course is effective in improving exam scores?

True or False: When the sample sizes are equal, the pooled variance of the two groups is the average of the 2 sample variances.

SCENARIO 10-7 -Referring to Scenario 10-7, the hypotheses that the buyer should test are a null hypothesis that ________ versus an alternative hypothesis that ________.

SCENARIO 10-3 -Referring to Scenario 10-3, suppose = 0.05.Which of the following represents the correct Conclusion?

SCENARIO 10-7 -Referring to Scenario 10-7, what is the 99% confidence interval estimate for the mean difference in prices?

SCENARIO 10-2 A researcher randomly sampled 30 graduates of an MBA program and recorded data concerning their starting salaries.Of primary interest to the researcher was the effect of gender on starting salaries.The result of the pooled-variance t-test of the mean salaries of the females (Population 1)and males (Population 2)in the sample is given below. -Referring to Scenario 10-2, what is the 99% confidence interval estimate for the difference between two means?

SCENARIO 10-5 10-16 Two-Sample Tests -Referring to Scenario 10-5, at the 0.05 level of significance, the decision for this hypothesis test Would be:

A powerful women's group has claimed that men and women differ in attitudes about sexual discrimination.A group of 50 men (group 1)and 40 women (group 2)were asked if they thought sexual discrimination is a problem in the United States.Of those sampled, 11 of the men and 19 of the women did believe that sexual discrimination is a problem.Construct a 90% confidence interval estimate of the difference between the proportion of men and women who believe that sexual discrimination is a problem.

SCENARIO 10-4 Two samples each of size 25 are taken from independent populations assumed to be normally distributed with equal variances.The first sample has a mean of 35.5 and standard deviation of 3.0 while the second sample has a mean of 33.0 and standard deviation of 4.0. -Referring to Scenario 10-4, a two-tail test of the null hypothesis of no difference would _______ (be rejected/not be rejected)at the = 0.05 level of significance.

True or False: For all two-sample tests, the sample sizes must be equal in the two groups.

A powerful women's group has claimed that men and women differ in attitudes about sexual discrimination.A group of 50 men (group 1)and 40 women (group 2)were asked if they thought sexual discrimination is a problem in the United States.Of those sampled, 11 of the men and 19 of the women did believe that sexual discrimination is a problem.Construct a 95% confidence interval estimate of the difference between the proportion of men and women who believe that sexual discrimination is a problem.

SCENARIO 10-5 10-16 Two-Sample Tests -Referring to Scenario 10-5, the value of the standard error of the difference scores is

True or False: When you test for differences between the means of two independent populations, you can only use a two-tail test.

SCENARIO 10-7 -Referring to Scenario 10-7, what is the 95% confidence interval estimate for the mean difference in prices?

A powerful women's group has claimed that men and women differ in attitudes about sexual discrimination.A group of 50 men (group 1)and 40 women (group 2)were asked if they thought sexual discrimination is a problem in the United States.Of those sampled, 11 of the men and 19 of the women did believe that sexual discrimination is a problem.Construct a 99% confidence interval estimate of the difference between the proportion of men and women who believe that sexual discrimination is a problem.

SCENARIO 10-5 10-16 Two-Sample Tests -True or False: Referring to Scenario 10-5, you must assume that the population of difference scores is normally distributed.