Exam 10: Two-Sample Tests of Hypothesis

A local retail business wishes to determine if there is a difference in preferred indoor temperature between men and women. A random sample of data is collected, with the following results (note: there are slight differences between Excel and MegaStat output in this test): What is the degree of freedom?

An investigation of the effectiveness of a training program to improve customer relationships included a pre-training and post-training customer survey. To compare the differences, they computed (post-training survey score - pre-training survey score). Seven customers were randomly selected and completed both surveys. The results follow: This analysis is an example of _____________.

How is a pooled estimate represented?

The results of a mathematics placement exam at Mercy College for two campuses are as follows: What is the null hypothesis if we want to test the hypothesis that the mean score on Campus 1 is higher than on Campus 2?

To compare the effect of weather on sales of soft drinks, a soda manufacturer sampled two regions of the country with the following results. Is there a difference in sales between the 2 regions? i. The null hypothesis is p_a - p_b = 0. ii. The alternate hypothesis is p_a - p_b $\neq$ 0. iii. If $\alpha$ = 0.01 and the z-statistic were calculated to be -1.96, your decision would be to fail to reject.

An investigation of the effectiveness of a training program to improve customer relationships included a pre-training and post-training customer survey. To compare the differences, they computed (post-training survey score - pre-training survey score). Seven customers were randomly selected and completed both surveys. The results follow: Was the training effective in improving customer relationships when tested at a 0.05 level of significance?

A local retail business wishes to determine if there is a difference in preferred indoor temperature between men and women. A random sample of data is collected, with the following results (note: there are slight differences between Excel and MegaStat output in this test): Using a 0.05 level of significance, can we conclude that there is indeed a difference in the temperature that men prefer compared to women? What is the null hypothesis if we assume men to be group 1 and women group 2?

A local retail business wishes to determine if there is a difference in preferred indoor temperature between men and women. A random sample of data is collected, with the following results (note: there are slight differences between Excel and MegaStat output in this test): If you use the 5% level of significance, what is the critical t value?

A national manufacturer of ball bearings is experimenting with two different processes for producing precision ball bearings. It is important that the diameters be as close as possible to an industry standard. The output from each process is sampled and the average error from the industry standard is calculated. The results are presented below: The researcher is interested in determining whether there is evidence that the two processes yield different average errors. This example is what type of test?

To compare the effect of weather on sales of soft drinks, a soda manufacturer sampled two regions of the country with the following results. Is there a difference in sales between the 2 regions? i. The null hypothesis is p_a - p_b = 0. ii. The alternate hypothesis is p_a - p_b $\neq$ 0. iii. Using the 1% level of significance, the critical value is $\pm$ 2.58.

If the null hypothesis that two means are equal is true, 97% of the computed-values will lie between what two values?

To compare the effect of weather on sales of soft drinks, a soda manufacturer sampled two regions of the country with the following results. Is there a difference in sales between the 2 regions? i. The alternate hypothesis is p_a - p_b $\neq$ 0. ii. The pooled estimate of the population proportion is 0.36. iii. Using the 1% level of significance, the critical value is $\pm$ 1.96.

An investigation of the effectiveness of a training program to improve customer relationships included a pre-training and post-training customer survey. To compare the differences, they computed (post-training survey score - pre-training survey score). Seven customers were randomly selected and completed both surveys. The results follow: For a 0.05 significance level, determine the critical value and the calculated value of the test statistic?

Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $1000) for five products both ways. Based on the following results, is LIFO more effective in keeping the value of his inventory lower? What is the value of calculated t?

i. We use the pooled estimate of the proportion in testing the difference between two population proportions when the samples are not chosen independently. ii. The pooled estimate of the proportion is found by dividing the total number of samples by the total number of successes. iii. A committee studying employer-employee relations proposed that each employee would rate his or her immediate supervisor and in turn the supervisor would rate each employee. To find reactions regarding the proposal, 120 office personnel and 160 plant personnel were selected at random. Seventy-eight of the office personnel and 90 of the plant personnel were in favour of the proposal. Computed z= 1.48. At the 0.05 level, it was concluded that there is sufficient evidence to support the belief that the proportion of office personnel in favour of the proposal is greater than that of the plant personnel.

Of 150 adults who tried a new peach-flavoured peppermint patty, 87 rated it excellent. Of 200 children sampled, 123 rated it excellent. Using the 0.10 level of significance, can we conclude that there is a significant difference in the proportion of adults and the proportion of children who rate the new flavour as excellent? State the decision rule, the value of the test statistic, and your decision.

Married women are more often than not working outside the home on at least a part-time basis, as do most mannered men. Does a husband's employment status affect his wife's well-being? In an attempt to answer this question, 20 married female professionals were surveyed as to their job satisfaction. In this sample, 15 husbands were employed, and 5 were unemployed. The Learning Objective of the study was to compare the mean job satisfaction levels of the married women with working husbands, with the mean job satisfaction levels of the married women with husbands that stayed at home. The test statistic for this problem has what type of distribution?

Married women are more often than not working outside the home on at least a part-time basis, as do most mannered men. Does a husband's employment status affect his wife's well-being? In an attempt to answer this question, 75 married female professionals were surveyed as to their job satisfaction. In this sample, 45 husbands were employed, and 30 were unemployed. The Learning Objective of the study was to compare the mean job satisfaction levels of the married women with working husbands, with the mean job satisfaction levels of the married women with husbands that stayed at home. The test statistic for this problem has what type of distribution?

The results of a mathematics placement exam at Mercy College for two campuses are as follows: What is the p-value if the computed test statistic is 4.1?

When is it appropriate to use the paired difference t-test?