H0:μ ≥ 70
H1:μ < 70
ts: t= (X-70)/ (3/√16) = t0
p-value = P( t<t0 ) = 0.01 查表得 t0 = -2.602
(X-70)/ (3/√16) = -2.602 平均值X=68.0485
H0:μ ≥ 69
H1:μ < 69
α=0.1 RR={t < t0.1(15)=-1.341}
ts: t= (68.0485-69)/ (3/√16) = -1.269 → Re H0
結論:沒有證據顯示μ < 69