Exam 10: Two-Sample Tests of Hypothesis

i. The paired difference test has (n1 + n2 - 2) degrees of freedom. ii. The paired t test is especially appropriate when the sample sizes of two groups are the same. Iii) A statistics professor wants to compare grades of two different groups of students taking the same course in two different sections. This is an example of a paired sample.

Of 250 adults who tried a new multi-grain cereal, Wow!, 187 rated it excellent; of 100 children sampled, 66 rated it excellent. What test statistic should we use?

i. If the null hypothesis states that there is no difference between the mean income of males and the mean income of females, then the test is one-tailed. ii. If we are testing for the difference between two population means, it is assumed that the sample observations from one population are independent of the sample observations from the other population. Iii) If we are testing for the difference between two population means, it is assumed that the two Populations are approximately normal and have equal variances.

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?

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 $000) 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 decision at the 5% 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): What is the alternate 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: If you were to use Excel's Data Analysis to assist in your solution to this problem, which test would you use?

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?

i. If the null hypothesis states that there is no difference between the mean income of males and the mean income of females, then the test is one-tailed. Ii) If we are testing for the difference between two population means, it is assumed that the sample observations from one population are independent of the sample observations from the other population. Iii) The critical value of t for the claim that the difference of two means is less than zero with = 0.025 and sample sizes of nine and seven, is -2.179.

How is a pooled estimate represented?

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 $000) 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 alternate hypothesis?

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. What is the null hypothesis?

i. If the null hypothesis states that there is no difference between the mean income of males and the mean income of females, then the test is one-tailed. Ii) If we are testing for the difference between two population means, it is assumed that the sample observations from one population are independent of the sample observations from the other population. Iii) When sample sizes are less than 30, a test for the differences between two population means has n - 1 degrees of freedom.

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 $000) for five products both ways. Based on the following results, is LIFO more effective in keeping the value of his inventory lower? This example is what type of test?

A recent study compared the time spent together by single and dual- earner couples. According to the records kept during the study, the mean amount of time spent together watching TV among single- earner couples was 65 minutes per day, with a standard deviation of 15.5 minutes. For the dual-earner couples, the mean time was 48.4 and the standard deviation was 18.1. At a 0.01 significance level, can we conclude that the single-earner couples on average spend more time watching TV together? There were 15 single-earner and 12 dual-earner couples studied. State the decision rule, the value of the test statistic, and your decision.

i. If we are testing for the difference between two population means, it is assumed that the sample observations from one population are independent of the sample observations from the other population. Ii) If we are testing for the difference between two population means, it is assumed that the two Populations are approximately normal and have equal variances. Iii) When sample sizes are less than 30, a test for the differences between two population means has n - 1 degrees of freedom.

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 $000) 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 decision at the 5% level of significance?

Suppose we are testing the difference between two proportions at the 0.05 level of significance. If the computed z is -1.07, what is our decision?

The employees at the East Vancouver office of a multinational company are demanding higher salaries than those offered at the company office located in Oshawa Ontario. Their justification for the pay difference is that the difference between the average price of single-family houses in East Vancouver and that in Oshawa is more than $60,000. Before making a decision, the company management wants to study the difference in the prices of single-family houses for sale at the two locations. The results of their search of recent house sales are as follows (in $000, rounded to the nearest thousand): Assuming that the population distributions are approximately normal, can we conclude at the 0.05 significance level that the difference between the two population means is greater than $60,000? If you use the 5% level of significance, what is the critical t value?

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 $000) for five products both ways. Based on the following results, is LIFO more effective in keeping the value of his inventory lower? If you use the 5% level of significance, what is the critical t value?