Part 4: Unbalanced 2-Way (Fixed Effects) ANOVA Dataset: celebrityendorse_attention . csv Source: P. -S. Wei, H. -P. Lu (2013). "An examination of the Celebrity Endorsements and Online Customer Reviews Influence Female Consumers' Shopping Behavior, " Computers in Human Behavior, Vol. 29, pp. 193-201. Description: Experiment with 2-factors: Product (1=Shoes, 2=Ink Toner ) and Endorser (1=Celebrity, 2=Online customer) . Completely Randomized (Between Subjects ) Design. Data simulated to match trt means and SDs. Response is subjects' attention score (average of 3 1-5 responses). Variable names : trt_group /* 1=shoes/celeb, 2=shoes/online, 3=toner/celeb, 4=toner/online product * 1= shoes, 2=ink toner */ endorser * 1=celebrity, 2=online customer * / shoe * 1=shoe, 0=toner * / celebrity /* 1=celebrity, 0=online customer * / attention /* response variable */ Fit the 2-Way ANOVA model as a regression model with X1 = 1 if shoes, -1 if Toner; and X2 = 1 if Celebrity, -1 if online customer. Test for interaction, and main effects. . Use the aov function in R. Test for main interaction and main effects. (use the contrasts=c("contr.sum" "contr.poly") option) Compare the results