Exam 10: Two-Sample Tests

TABLE 10-15 The table below presents the summary statistics for the starting annual salaries (in thousands of dollars)for individuals entering the public accounting and financial planning professions. Sample I (public accounting): ₁ = 60.35,S₁ = 3.25,n₁ = 12 Sample II (financial planning): ₂ = 58.20,S₂ = 2.48,n₂ = 14 Test whether the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning assuming that the two population variances are the same. -Referring to Table 10-15,suppose α = 0.10.Which of the following represents the result of the relevant hypothesis test?

TABLE 10-9 The following Excel output contains the results of a test to determine whether the proportions of satisfied customers at two resorts are the same or different. -Referring to Table 10-9,allowing for 1% probability of committing a Type I error,what are the decision and conclusion on testing whether there is any difference in the proportions of satisfied customers in the two resorts?

TABLE 10-15 The table below presents the summary statistics for the starting annual salaries (in thousands of dollars)for individuals entering the public accounting and financial planning professions. Sample I (public accounting): ₁ = 60.35,S₁ = 3.25,n₁ = 12 Sample II (financial planning): ₂ = 58.20,S₂ = 2.48,n₂ = 14 Test whether the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning assuming that the two population variances are the same. -Referring to Table 10-15,suppose α = 0.05.Which of the following represents the result of the test on a difference in the variances?

The F distribution is symmetric.

TABLE 10-5 To test the effectiveness of a business school preparation course,8 students took a general business test before and after the course.The results are given below. -Referring to Table 10-5,at the 0.05 level of significance,the conclusion for this hypothesis test is that there is sufficient evidence that

When testing H₀: π₁ - π₂ ≤ 0 versus H₁: π₁ - π₂ > 0,the observed value of the Z test statistic was found to be -2.13.The p-value for this test is

TABLE 10-15 The table below presents the summary statistics for the starting annual salaries (in thousands of dollars)for individuals entering the public accounting and financial planning professions. Sample I (public accounting): ₁ = 60.35,S₁ = 3.25,n₁ = 12 Sample II (financial planning): ₂ = 58.20,S₂ = 2.48,n₂ = 14 Test whether the mean starting annual salaries for individuals entering the public accounting professions is higher than that of financial planning assuming that the two population variances are the same. -Referring to Table 10-15,what assumptions are necessary for testing whether there is evidence of a difference in the variances to be valid?

TABLE 10-12 A quality control engineer is in charge of the manufacture of computer disks.Two different processes can be used to manufacture the disks.He suspects that the Kohler method produces a greater proportion of defects than the Russell method.He samples 150 of the Kohler and 200 of the Russell disks and finds that 27 and 18 of them,respectively,are defective.If Kohler is designated as "Group 1" and Russell is designated as "Group 2," perform the appropriate test at a level of significance of 0.01. -Referring to Table 10-12,the same decision would be made with this test if the level of significance had been 0.05 rather than 0.01.

TABLE 10-12 A quality control engineer is in charge of the manufacture of computer disks.Two different processes can be used to manufacture the disks.He suspects that the Kohler method produces a greater proportion of defects than the Russell method.He samples 150 of the Kohler and 200 of the Russell disks and finds that 27 and 18 of them,respectively,are defective.If Kohler is designated as "Group 1" and Russell is designated as "Group 2," perform the appropriate test at a level of significance of 0.01. -Referring to Table 10-12,the null hypothesis should be rejected.

The sample size in each independent sample must be the same if we are to test for differences between the means of two independent populations.

The F test used for testing the difference in two population variances is always a one-tail test.

A Marine drill instructor recorded the time in which each of 11 recruits completed an obstacle course both before and after basic training.To test whether any improvement occurred,the instructor would use a t-distribution with 10 degrees of freedom.

TABLE 10-3 A real estate company is interested in testing whether the mean time that families in Gotham have been living in their current homes is less than families in Metropolis.Assume that the two population variances are equal.A random sample of 100 families from Gotham and a random sample of 150 families in Metropolis yield the following data on length of residence in current homes. Gotham: G = 35 months, SG² = 900 Metropolis: M = 50 months,SM² = 1050 -Referring to Table 10-3,suppose α = 0.01.Which of the following represents the correct conclusion?

The test for the equality of two population variances assumes that each of the two populations is normally distributed.

TABLE 10-1 Are Japanese managers more motivated than American managers? A randomly selected group of each were administered the Sarnoff Survey of Attitudes Toward Life (SSATL),which measures motivation for upward mobility.The SSATL scores are summarized below. -Referring to Table 10-1,judging from the way the data were collected,which test would likely be most appropriate to employ?

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

TABLE 10-5 To test the effectiveness of a business school preparation course,8 students took a general business test before and after the course.The results are given below. -Referring to Table 10-5,you must assume that the population of difference scores is normally distributed.

For all two-sample tests,the sample sizes must be equal in the two groups.

In testing for differences between the means of 2 related populations where the variance of the differences is unknown,the degrees of freedom are

TABLE 10-10 A corporation randomly selects 150 salespeople and finds that 66% who have never taken a self-improvement course would like such a course.The firm did a similar study 10 years ago in which 60% of a random sample of 160 salespeople wanted a self-improvement course.The groups are assumed to be independent random samples.Let π₁ and π₂ represent the true proportion of workers who would like to attend a self-improvement course in the recent study and the past study,respectively. -Referring to Table 10-10,what is/are the critical value(s)when performing a Z test on whether population proportions are different if α = 0.05?