Exam 10: Comparisons Involving Means, Experimental Design and Analysis of Variance

The following data present the number of computer units sold per day by a sample of 6 salespersons before and after a bonus plan was implemented. At 95% confidence, test to see if the bonus plan was effective. That is, did the bonus plan actually increase sales? Let d = Before - After.

A test on world history was given to a group of individuals before and also after a film on the history of the world was presented. The results are given below. We want to determine if the film significantly increased the test scores. (For the following matched samples, let the difference "d" be d = after - before.) a.Give the hypotheses for this problem. b.Compute the test statistic. c.At 95% confidence, test the hypotheses.

In ANOVA, which of the following is not affected by whether or not the population means are equal?

For testing the following hypothesis at 95% confidence, the null hypothesis will be rejected if $\mu$ ₁ - $\mu$ ₂ $\le$ 0 H _$\alpha$ : $\mu$ ₁ - $\mu$ ₂ > 0

In order to estimate the difference between the average daily sales of two branches of a department store, the following data has been gathered. a.Determine the point estimate of the difference between the means. b.Determine the degrees of freedom for this interval estimation. c.Compute the margin of error. d.Develop a 95% confidence interval for the difference between the two population means.

An ANOVA procedure is used for data obtained from five populations. five samples, each comprised of 20 observations, were taken from the five populations. The numerator and denominator (respectively) degrees of freedom for the critical value of F are

The required condition for using an ANOVA procedure on data from several populations is that the

Exhibit 10-12 In a completely randomized experimental design involving five treatments, 13 observations were recorded for each of the five treatments (a total of 65 observations). The following information is provided. -Refer to Exhibit 10-12. The test statistic is

Six observations were selected from each of three populations. The data obtained is shown below. Test at the $\alpha$ = 0.05 level to determine if there is a significant difference in the means of the three populations. Use both the critical value and the p-value approaches.

The critical F value with 8 numerator and 29 denominator degrees of freedom at $\alpha$ = 0.01 is

The following are the test scores of two samples of students from University A and University B on a national statistics examination. Develop a 95% confidence interval estimate for the difference between the mean scores of the two populations.

The variable of interest in an ANOVA procedure is called

Exhibit 10-13 Part of an ANOVA table is shown below. -Refer to Exhibit 10-13. The mean square between treatments (MSTR) is

Exhibit 10-1 Salary information regarding male and female employees of a large company is shown below. -Refer to Exhibit 10-1. The 95% confidence interval for the difference between the means of the two populations is

The management of Chattanooga Paper Corporation wants to determine whether there is a significant difference in the thickness of papers produced at their two existing plants. The following data has been accumulated for this test. The degrees of freedom (df) for this problem are given to be df = 80. a.Compute a 95% confidence interval for the difference in the average thickness of papers produced at the two plants. b.Is there conclusive evidence that the average thickness in one plant is significantly more than the other? If yes, which plant? Explain, using the results of part (a). Do not perform any test.

Consider the following results for two samples randomly taken from two populations. a.Determine the degrees of freedom for the t distribution. b.At 95% confidence, what is the margin of error? c.Develop a 95% confidence interval for the difference between the two population means.

A random sample of 89 tourists in Chattanooga showed that they spent an average of $2,860 (in a week) with a standard deviation of $126; and a sample of 64 tourists in Orlando showed that they spent an average of $2,935 (in a week) with a standard deviation of $138. We are interested in determining if there is any significant difference between the average expenditures of those who visited the two cities? a.Determine the degrees of freedom for this test. b.Compute the test statistic. c.Compute the p-value. d.What is your conclusion? Let $\alpha$ = .05.

In order to estimate the difference between the average age of male and female employees at the Young Corporation, the following information was gathered. Develop a 95% confidence interval estimate for the difference between the average age of male and female employees at the Young Corporation.

In order to compare the life expectancies of three different brands of printers, eight printers of each brand were randomly selected. Information regarding the three brands is shown below. a.Compute the overall mean. b.State the null and alternative hypotheses to be tested. c.Show the complete ANOVA table for this test including the test statistic. d.The null hypothesis is to be tested at 95% confidence. Determine the critical value for this test. What do you conclude? e. Determine the p-value and use it for the test.

Exhibit 10-4 The following information was obtained from independent random samples. Assume normally distributed populations with equal variances. -Refer to Exhibit 10-4. The degrees of freedom for the t-distribution are