# Business Statistics And Analytics In Practice 9th Edition By Bruce Bowerman – Test Bank

Chapter 11 Statistical Inferences Based on Two Samples

1) An independent samples experiment is an experiment in which there is no relationship between the measurements in the different samples.

Answer: TRUE

Explanation: Different samples from the first population would give different values of the mean, and different samples from the second population would give different values of the mean.

Difficulty: 1 Easy

Topic: Comparing Two Population Means by Using Independent Samples

Learning Objective: 11-01 Compare two population means when the samples are independent.

Bloom’s: Remember

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

2) When testing the difference between two proportions selected from populations with large independent samples, the z test statistic is used.

Answer: TRUE

Explanation: This is because we can estimate the standard deviation via the two proportions.

Difficulty: 1 Easy

Topic: Comparing Two Population Proportions by Using Large, Independent Samples

Learning Objective: 11-04 Compare two population proportions using large independent samples.

Bloom’s: Remember

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

3) In forming a confidence interval for μ1 − μ2, only two assumptions are required: independent samples and sample sizes of at least 30.

Answer: FALSE

Explanation: The assumptions are independent samples, equal variances, and either sample sizes are large or the sampled populations are normally distributed.

Difficulty: 1 Easy

Topic: Comparing Two Population Means by Using Independent Samples

Learning Objective: 11-01 Compare two population means when the samples are independent.

Bloom’s: Remember

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

4) In an experiment involving matched pairs, a sample of 12 pairs of observations is collected. The degrees of freedom for the t statistic is 10.

Answer: FALSE

Explanation: Degrees of freedom is n − 1 = 12 − 1 = 11

Difficulty: 1 Easy

Topic: Paired Difference Experiments

Learning Objective: 11-03 Compare two population means when the data are paired.

Bloom’s: Apply

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

5) When comparing two independent population means, if n1 = 13 and n2 = 10, degrees of freedom for the t statistic is 22.

Answer: FALSE

Explanation: Degrees of freedom = n1 + n2 − 2 = 13 + 10 − 2 = 21

Difficulty: 1 Easy

Topic: Comparing Two Population Means by Using Independent Samples

Learning Objective: 11-01 Compare two population means when the samples are independent.

Bloom’s: Apply

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

6) There are two types of machines, called type A and type B. Both type A and type B can be used to produce a certain product. The production manager wants to compare efficiency of the two machines. He assigns each of the 15 workers to both types of machines to compare their hourly production rate. In other words, each worker operates machine A and machine B for one hour each. These two samples are independent.

Answer: FALSE

Explanation: This is a paired sample because both machines have the same operators.

Difficulty: 2 Medium

Topic: Paired Difference Experiments

Learning Objective: 11-02 Recognize when data come from independent samples and when they are paired.

Bloom’s: Analyze

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

7) In testing the difference between two means from two independent populations, the sample sizes do not have to be equal.

Answer: TRUE

Explanation: Each sample size needs to be large.

Difficulty: 1 Easy

Topic: Comparing Two Population Means by Using Independent Samples

Learning Objective: 11-01 Compare two population means when the samples are independent.

Bloom’s: Remember

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

8) In testing the difference between the means of two normally distributed populations using large independent random samples, the sample sizes from the two populations must be equal.

Answer: FALSE

Explanation: Sample sizes do not have to be equal to test the differences of the means.

Difficulty: 1 Easy

Topic: Comparing Two Population Means by Using Independent Samples

Learning Objective: 11-01 Compare two population means when the samples are independent.

Bloom’s: Understand

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

9) In testing the difference between the means of two normally distributed populations using independent random samples, the alternative hypothesis always indicates no difference between the two specified means.

Answer: FALSE

Explanation: The alternative hypothesis can be a difference or greater than or less than.

Difficulty: 1 Easy

Topic: Comparing Two Population Means by Using Independent Samples

Learning Objective: 11-01 Compare two population means when the samples are independent.

Bloom’s: Remember

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

10) In testing the difference between the means of two normally distributed populations using independent random samples, we can only use a two-sided test.

Answer: FALSE

Explanation: Using the critical value rules, we should use a two-sided test if the test is of no differences between the two samples. If we are looking at a greater than or less than difference, we would use a one-sided test.

Difficulty: 1 Easy

Topic: Comparing Two Population Means by Using Independent Samples

Learning Objective: 11-01 Compare two population means when the samples are independent.

Bloom’s: Remember

AACSB: Reflective Thinking

Accessibility: Keyboard Navigation

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