Exam 10: Two-Sample Hypothesis Tests

Random samples of Tuesday and Friday withdrawals from a college-campus ATM were compared to see whether or not there was a difference in the means.The results shown below are from MegaStat.Analyze these results thoroughly.

Two well-known aviation training schools are being compared using random samples of their graduates.It is found that 70 of 140 graduates of Fly-More Academy passed their FAA exams on the first try,compared with 104 of 260 graduates of Blue Yonder Institute.To compare the pass rates,the pooled proportion would be:

In a random sample of patient records in Cutter Memorial Hospital,six-month postoperative exams were given in 90 out of 200 cases,while in Paymor Hospital such exams were given in 110 out of 200 cases.The pooled proportion is:

A medical researcher wondered if there is a significant difference between the mean birth weight of boy and girl babies.Random samples of 5 babies' weights (pounds)for each gender showed the following: To test the researcher's hypothesis,we should use the:

In a random sample of patient records in Cutter Memorial Hospital,six-month postoperative exams were given in 90 out of 200 prostatectomy patients,while in Paymor Hospital such exams were given in 110 out of 200 cases.In a left-tailed test for equality of proportions,the p-value is:

The F test is used to test for the equality of two population variances.

Which is not true of the two-tailed F-test for equality of variances?

Two well-known aviation training schools are being compared using random samples of their graduates.It is found that 70 of 140 graduates of Fly-More Academy passed their FAA exams on the first try,compared with 104 of 260 graduates of Blue Yonder Institute.In a right-tailed test,the p-value is .0275,so at  = .025 we should:

A corporate analyst is testing whether mean inventory turnover has increased.Inventory turnover in six randomly chosen product distribution centers (PDCs)is shown. The degrees of freedom for the appropriate test would be:

At Huge University,a sample of 200 business school seniors showed that 26 planned to pursue an MBA degree,compared with 120 of 800 arts and sciences seniors.We want to know if the proportion is higher in the arts and sciences group.The p-value for a left-tailed test is approximately:

In a test of a new surgical procedure,the five most respected surgeons in FlatBroke Township were invited to Carver Hospital.Each surgeon was assigned two patients of the same age,gender,and overall health.One patient was operated upon in the old way,and the other in the new way.Both procedures are considered equally safe.The surgery times are shown below: The time (in minutes)to complete each procedure was carefully recorded.In a right-tailed test for a difference of means,the test statistic is:

John wants to compare two means.His sample statistics were and .Assuming equal variances,the pooled variance is:

A corporate analyst is testing whether mean inventory turnover has increased.Inventory turnover in six randomly chosen product distribution centers (PDCs)is shown. The value of the test statistic is:

A medical researcher compared the variances in birth weights for five randomly chosen babies of each gender,with the MegaStat results shown below. The population variances:

When using independent samples to test the difference between two population means,it is desirable but not necessary for the sample sizes to be the same.