Say a regression equation if fit to data, and the correlation coefficient estimate ,R ,between X and Y is 0.5. State if true or false. a. The slope of the regression line is 0.5. b. The regression model with X explains 50% of the variation in Y , c. 25% of the variation in Y is explained by X. d. 50% of the variation in Y is explained by X. e. X is positively associated with Y . f. Even if X and Y have a non linear relationship, the value of 0.5 can be used to measure the association between X and Y.