Answer and explain the reason with showing work

19. Consider the information given above for Question 18 once again. The proportion of the variance in yearly winnings explained by the variance in the number of hours of study per day is approximately: A 0.15 B. 0.02 0.50 D 0.35 20. In a simple regression, if the estimated slope coefficient bz = -3 and the coefficient of determination is 0.25, then the sample correlation coefficient between X and Y (xy) is: A -0.5 B. -0.75 0.5 D. 0.75