(8)设X1,X2,···,X9是来自正态总体N(μ,σ^2)的样本, _(1)=dfrac (1)(6)sum _(i=1)^6(X)_(i) , _(2)=-|||-dfrac (1)(3)sum _(i=7)^9X , ^2=dfrac (1)(2)sum _(i=7)^9(({X)_(i)-(Y)_(2))}^2 则统计量 =dfrac (sqrt {2)((Y)_(1)-(Y)_(2))}(S) 服从自由度为 __ 的-|||-__ 分布.

1.设X1,X2,···,xn来自总体X的样本, (X)=(sigma )^2, overline (X)=dfrac (1)(n)sum _(i=1)^n(X

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

(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,···,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) ,

5、设 sim N(1,9) ,X1,X2,···X9为X的样本,记 overline (X)=dfrac (1)(n)sum _(i=1)^n(X)_(i)

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)

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

7.设X1,X2,···, _(n)(ngeqslant 2) 为来自正态总体N(μ,1)的简单随机样本,若 overline (X)=-|||-dfrac (

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