In the same study described in Problem 4, media usage versus household income also was considered. The media usage indices for the various media and income levels follow.

(a) List the factors and the number of levels of each factor.

(b) Assume there is no interaction between the factors. Use two-way ANOVA and the following Minitab printout to determine if there is a difference in population mean index based on income. Use a = 0.05.

(c) Determine if there is a difference in population mean index based on media. Use a = 0.05.

Media Cable Prime-Time Radio 89 100 106 107 Newspaper Magazine Income Level Less than $20,000 $20,000-$39,999 $40,000-$74,999 $75,000 or more Network 78 97 113 121 TV 112 105 92 94 91 100 105 105 80 97 121 Minitab Printout for Media/Income Data Analysis of Variance for Index Source DF MS 1078 15 1558 2651 359 2.77 0.088 0.998 Media Error Total 0.03 12 130 19