设X1,X2,···,Xn是来自正态总体N(μ,σ^2)的简单随机样-|||-本,X是样本均值,记-|||-({S)_(1)}^2=dfrac (1)(n-1)sum _(i=1)^n(({X)_(i)-overline (X))}^2, ({S)_(2)}^2=dfrac (1)(n)sum _(i=1)^n(({X)_(i)-overline (X))}^2,-|||-({S)_(3)}^2=dfrac (1)(n-1)sum _(i=1)^n(({X)_(i)-mu )}^2, ({S)_(4)}^2=dfrac (1)(n)sum _(i=1)^n(({X)_(i)-mu )}^2,-|||-则服从自由度为 n-1 的t分布的随机变量是 () .-|||-(A) =dfrac (overline {X)-mu }({S)_(1)/sqrt (n-1)}; (B) =dfrac (X-mu )({S)_(2)sqrt (n-1)}-|||-(C) =dfrac (overline {X)-mu }({S)_(3)sqrt (n-1)}; (D) =dfrac (X-mu )({S)_(4)sqrt (n-1)}

设(X1,X2,···,Nn)是来自正态总体N (μ,σ^2)的-|||-简单随机样本,X是样本均值,记-|||-({S)_(1)}^2=dfrac (1)(n

8.设X1,X2,···,Xn是来自总体N(μ,σ^2 )的简单随机样本,X是样本均值,记 ({S)_(1)}^2=-|||-dfrac (1)(n-1)sum

(16)设X1,X2,···,xn为来自标准正态总体X的简单随机样本,记 overline (X)=dfrac (1)(n)sum _(i=1)^n(X)_(i

设X1,X2,···, _(n)(ngt 2) 为来自总体N(0,1)的简单随机样-|||-本,X为样本均值,记 overline (X)=dfrac (1)(

5.11 设(X1,X2,···Xn, _(n)+1) 是正态总体N(μ,σ^2)的样本, overline (X)=-|||-dfrac (1)(n)sum

设X1,X2,···, _(n)(ngeqslant 2) 为来自总体N(μ,1)的简单随机样本,-|||-记 overline (x)=dfrac (1)(n

设X1,X2,···,Xn是正态总体N(μ,σ^2 )的样本,则 dfrac (1)(n)sum _(i=1)^n(({X)_(i)-overline (X))

4.样本X1,X2,···Xn来自总体 sim N(0,1) , overline (X)=dfrac (1)(n)sum _(i=1)^n(X)_(i) ,

4.设X1,.,Xn为正态总体 sim N(mu ,(sigma )^2) 的样本,记 ^2=dfrac (1)(n-1)sum _(i=1)^n(({X)_(

设X1,X2,···,Xn, _(n+1) 是来自正态总体N(μ,σ ^2)的样本,设X1,X2,···,Xn, _(n+1) 是来自正态总体N(μ,σ ^2)