Question

c. Use MS Excel Data Analysis ToolPak to perform two (2) simple regressions, one using Quality as the response variable and Helpfulness as the predictor variable (Model 1) and the other using Quality as the response variable and raterInterest as the predictor variable (Model 2). Compare the two models in terms of R² value. Which of these two variables is a better predictor of Quality? Explain why.

model 1			model 2
Regression Statistics			Regression Statistics
Multiple R	0.981031		Multiple R	0.470669
R Square	0.962423		R Square	0.221529
Adjusted R Square	0.962319		Adjusted R Square	0.21939
Standard Error	0.163498		Standard Error	0.488182
Observations	366		Observations	366

Answer 1

Solution: The R-square value for model 1 is 0.9624, therefore, 96.24% of the variation in the dependent variable Quality is explained by the predictor variable Helpfulness.

The R-square for model 2 is 0.2215, therefore, 22.15% of the variation in the dependent variable Quality is explained by the predictor variable rater interest.

Since the R-square for mode1 is more than the R-square for model 2, therefore, Helpfulness is a better predictor of Quality.