16-17. Demonstrate that S2 = ni =1 e2 i >(n 2) is an unbiased estimator...

16-17. Demonstrate that S2

ε

= ni

=1 e2 i >(n − 2) is an unbiased estimator for σ2

ε .

(Hint: In d2 = 1n

ni

=1 e2 i set ei = −( ˆ β1 − β1)xi + εi − ¯ε. Then correct for the bias in E(d2) =

n−2 n σ2

ε .)