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)(n)sum _(i=1)^n(X)_(i), 记 _(i)=(X)_(i)-overline (X) ,i=1, 2 ,.,-|||-n.求:-|||-(1)Y1的方差D(Y ), i=1, 2,···,n;-|||-(2)Y1与Yn的协方差Cov(Y1,Yn).

[题目]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 _(i)=(X)_(i)-overlin

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

(8)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)su

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) ,

(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

4.设X1,X2,···,Xn为来自正态总体 sim N(0,1) 的简单随机样本, overline (X)=dfrac (1)(n)sum _(i=1)^n

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)

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 (

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

设X1,X2,···, _(n)(ngt 2) 为独立同分布的随机变量,且均服-|||-从N(0,1).记 overline (X)=dfrac (1)(n)s