Statistical Inferences Based on Two Samples Essay

6329 Words Oct 1st, 2011 26 Pages
Chapter 10
Statistical Inferences Based on Two Samples

True/False

1. An independent sample experiment is an experiment in which there is no relationship between the measurements in the different samples.
Answer: True Difficulty: Medium

2. When testing the difference between two proportions selected from populations with large independent samples, the Z test statistic is used.
Answer: True Difficulty: Medium

3. In forming a large sample confidence interval for [pic], two assumptions are required: independent samples and sample sizes of at least 30.
Answer: True Difficulty: Medium

4. In testing the equality of population variances, two assumptions are required: independent samples and normally distributed
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In testing for the equality of means from two independent populations, if the hypothesis of equal population means is rejected at α = .01, it will __________ be rejected at α = .05.
A) Always
B) Sometimes
C) Never
Answer: A Difficulty: Hard (REF)

24. A new company is in the process of evaluating its customer service. The company offers two types of sales: 1. Internet sales; 2. Store sales. The marketing research manager believes that the Internet sales are more than 10% higher than store sales. The null hypothesis would be:
A) Pinternet – Pstore > .10
B) Pinternet – Pstore < .10
C) Pinternet – Pstore ( .10
D) Pinternet – Pstore ( .10
E) Pinternet – Pstore = .10
Answer: D Difficulty: Medium
25. In order to test the effectiveness of a drug called XZR designed to reduce cholesterol levels, 9 heart patients' cholesterol levels are measured before they are given the drug. The same 9 patients use XZR for two continuous months. After two months of continuous use the 9 patients' cholesterol levels are measured again. The comparison of cholesterol levels before vs. after administering the drug is an example of testing the difference between:
A) Two means from independent populations.
B) Two population variances from independent populations.
C) Two population proportions.
D) Matched pairs from two dependent populations.
Answer: D Difficulty: Medium

26. In testing the difference between the means of two normally distributed populations

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