Consider the demonstration that E(bIV) converges to as the sample size increases, which begins with equations

Consider the demonstration that E(bIV) converges to β as the sample size increases, which begins with equations (10.33) and (10.34).

(a) Simplify equation (10.33) to obtain equation (10.34).

(b) Follow the argument of equations (10.15) and (10.16) to demonstrate that E(( z z ) ) i i − ε is approximately equal to COV(zi, εi).