Question

In an effort to promote a new product, a marketing firm asks participants to rate the effectiveness of ads that varied by length (short, long) and by type of technology (static, dynamic, interactive). Higher ratings indicated greater effectiveness.

Source of Variation	SS	df	MS	F
Length	15
Technology
Length × Technology	146
Error	570	114
Total	811

(a) Complete the F-table and make a decision to retain or reject the null hypothesis for each hypothesis test. (Assume experimentwise alpha equal to 0.05.)

Source of Variation	SS	df	MS	F
Length	15	1	2	3
Technology	4	5	6	7
Length × Technology	146	8	9	10
Error	570	114	11
Total	811	12

State the decision for the main effect of length.

Retain the null hypothesis. Reject the null hypothesis.    

State the decision for the main effect of technology.

Retain the null hypothesis. Reject the null hypothesis.    

State the decision for the interaction effect.

Retain the null hypothesis. Reject the null hypothesis.    

(b) Based on the results you obtained, what is the next step?

Compute pairwise comparisons for the technology factor. Compute simple main effect tests for the significant interaction.     No further analysis is needed, because none of the effects are significant. Compute pairwise comparisons for the length factor.

Answer 1