Please ignore question part (a), and I only need help on question 2(b) and 2(c) please. I'm having a tuff time dealing them.

Problem 2 (20 points) Consider a regression model in which one makes n observations on a variable Y, which varies with regressors X1, ...,Xp_1 according to Y = } +X1] + +Xplinl + E In matrix terms, 3' = XB + 8 where X is the n x p matrix with columns In, :1 , ..., zp_] and 2; contains all n values of the variables X;. Assume that the rank of X is p, so that the 'hat' matrix is H = X(X'X)"X'. (a) Write down the hat matrix 11 using the data matrix X from Problem 1. and verify that all the row sums are equal to one. ('3) Show 1111- I - - I _ _ i - ul