2. The usual normal theory test of H0 : 1 2 = 0 is the t-test based...

2. The usual normal theory test of H0 : μ1 −μ2 = δ0 is the t-test based on the statistic T =

X−Y −δ0 Sp(1/m+1/n)1/2 , where S2 p =

(m−1)S2 1 +(n−1)S2 2

m+n−2

.

Under H0, the statistic T has a t-distribution with N −2 d.f., provided that σ2 1 = σ2