1.Suppose Yi, i = 1, 2, …, N, is independently and identically distributed as N(0, σ^2)求:a): Show that E(Yi^2 / σ^2)=1b): Show that W=(1/σ^2) * ∑i=1,N * Yi^2 is distributed λ^2N (ps: λ是很像X的那个希腊字母, N是下标.)c): Show that E(W) = N.怕打的不清楚..附了张题目..