1. Consider that n subjects give data, (y, X1X12),..., (ynxnxn2), which are statistically independent and satisfy the model Yi = Bo + B(Xi x ) +Bz (Xzi Xz)+& - ,i=1,n where x and x are non-random; x is the sample mean of xk, k = 1,2; &'s are normally distributed random errors with mean zero and variance o (its value is unknown). a) Construct test for Ho: a + a = C and bB + b = C, at = 0.05, where all a's, b's, c's are given positive real numbers. b) Delete the intercept coefficient Po from the model. Construct test for significance of the regressor x.