Question 1. Show that the ridge estimator is the solution to the problem
Minimizeβ (β - β^)' X'X(β - β^)
subject to ββ' ≤ d2.
Question 2. Show that the least squares estimate of β (say β^(-i) with the ith observation deleted can be written in terms of the estimate based on all n points as
β^(-i) = β^- ei/(1-hii).(X'X)-1xi