Statistical Inferences Based on Two Samples Essay

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


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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