Question: The Style-Rite Company of Atlanta makes windbreaker jackets for people who play golf and who are active outdoors during the spring and fall months. The company recently developed a new material and is in the process of test-marketing jackets made from the material. As part of this test marketing effort, 10 people were each supplied with a jacket made from the original material and were asked to wear it for two months, washing it at least twice during that time. A second group of 10 people was each given a jacket made from the new material and asked to wear it for two months with the same washing requirements. Following the two-month trial period, the individuals were asked to rate the jackets on a scale of 0 to 100, with 0 being the worst performance rating and 100 being the best. The ratings for each material are shown as follows:
The company expects that, on the average, the performance ratings will be superior for the new material.
a. Examine the data given. What characteristics of these data sets would lead you to reject the assumption that the data came from populations that had normal distributions and equal variances?
b. Do the sample data support this belief at a significance level of 0.05? Discuss.