4 . (8 points) Suppose that the relationship between the independent variable* ( meaning height ) and dependent variable * ( meaning weight ) is described by a simple linear regression model with true regression line : " - 7 + 0. 5x, and ` = 3. ( a ) ( 2 pts) TIF question The interpretation of $ 1 = 0.5 means that the expected change in weight associated with a I unit increase* in height . ( T / F ) ( b ) ( 3 pts ) If* = 20 , what is the expected value of ! ?! ( C ) ( 3 pts ) If* = 20 , what is P [ { = 23 )