An advertising agency has been hired by a manufacturer of pens to develop an aqdvertising campaign for the upcoming holiday season. To prepare for this project, the research director decides to initiate a study of the effect of advertising on product perception. An experiment is designed to compare five different advertisements. Advertisement A greatly undersells the pen's characteristics. Advertisement B slightly undersells the pen's characteristics. Advertisment C slightly oversells the pen's characteristics. Advertisement D greatly oversells the pen's characteristics. Advertisement E attempts to correctly stat the pen's characteristics. A sample of 30 adults respondents, taken from a larger focus group, is randomly assigned to the five advertisements(so that there are six respondents to each). After reading the advertisement and developing a senseof "product expectation," all respondents unknowingly receive the same pen to evaluate. The respondents are permitted to test the pen and the plausibility of the advertising copy. The respondents are then asked to rate the penfrom 1 to 7 (lowest to highest) on the product characteristic scales of appearance, durability, and writing performance. The combined scores of three ratings (appearance, durability, and writing performance) for the 30 respondents in the data to the left.

a. At the 0.05 level of significance, is there evidence of a difference in the mean rating of the five advertisements?

b. If appropriate, determine which advertisements differin mean ratings.

c. At the 0.05 level of significance, is there evidenceof a difference in the variation in ratings among the five advertisements?

d. Which advertisement(s) should you use, and which advertisement(s) shoyuld you avoid?