4. For the data: (X1, X2,Y) = (1, 1, 7.2), (1, 0, 8.1), (0, 0, 9.8), (1, 0, 12.3), (1, 1, 12.9), consider the model: E(Y) Bo+ BX1 + B2X2. a) Let R(X) and R (X1, X2) denote the coefficients of determination in the regressions of Y on X and Y on X and X2 respectively. Compute R(X1), R 2|1 and R(X1, X2) from the given data. b) Derive a relationship between R (X1, X2) and (R(X1), R 2|1). c) Empirically verify the relationship obtained in (b) using the given data.