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As part of an evaluation program, a sporting goods retailer wanted to compare th

ID: 3149913 • Letter: A

Question

As part of an evaluation program, a sporting goods retailer wanted to compare the downhill coasting speeds of 4 brands of bicycles. She took 3 of each brand and determined their maximum downhill speeds. The results are presented in miles per hour in the table below.


True or False: Referring to Table 11-3, the test is less sensitive to the assumption that the population of speeds has the same variance for the 4 brands because the sample sizes of the 4 brands are equal.

Trial Barth Tornado Reiser Shaw 1 43 37 41 43 2 46 38 45 45 3 43 39 42 46

Explanation / Answer

As part of an evaluation program, a sporting goods retailer wanted to compare the downhill coasting speeds of 4 brands of bicycles. She took 3 of each brand and determined their maximum downhill speeds. The results are presented in miles per hour in the table below.

Trial

Barth

Tornado

Reiser

Shaw

1

43

37

41

43

2

46

38

45

45

3

43

39

42

46


True or False: Referring to Table 11-3, the test is less sensitive to the assumption that the population of speeds has the same variance for the 4 brands because the sample sizes of the 4 brands are equal.

A. True

B. False

Since the sample sizes of the 4 brands are equal, assumption that the population of speeds has the same variance is less sensitive on ANOVA.

The effect of inequality of variances is mitigated when the sample sizes are equal: The F test is fairly robust against inequality of variances if the sample sizes are equal.

Trial

Barth

Tornado

Reiser

Shaw

1

43

37

41

43

2

46

38

45

45

3

43

39

42

46