12.2 Consider a linear regression model with y = E(Y|x) = 51.6 + 4.7x. (a) (1m) What is the slope of the population regression line (b) (1m) Explain clearly what this slope says about the change in the Look up definition of slope mean of y for a change in x. (c) (1m) What is the subpopulation mean when x = 10? That is, what is E(Y|X = 10)? That is, what is the predicted value , when x = 10? HINT: SUB x=10 INTO EQUATION