An article10 used multiple regression to predict a measure of tolerance toward homosexuality.

(a) The researchers found that the effect of number of years of education varied from essentially no effect for political conservatives to a considerably positive effect for political liberals. Explain how this is an example of statistical interaction. Explain how it would be handled by a multiple regression model.

(b) The best predictor of tolerance toward homosexuality was educational level, with an estimated standardized regression coefficient of 0.21. Interpret. In comparing this effect with the effects of other predictors, explain the purpose of using standardized coefficients.