两个正态总体方差的检验(f检验).txt

两个正态总体方差的检验(F检验)的matlab程序

>>两个正态总体方差的检验(F检验) 
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推荐function [h,f,f1]=ftest0(X,Y,a,tail) 
%参考文献：《应用数理统计》（叶慈南编）p122. 
%两个正态总体方差的检验(F检验） 
%调用格式：[h,f,f1]=ftest0(X,Y,a,tail) 
%X,Y为样本，a为显著性水平 
%TAIL must be ''both'', ''right'', or ''left'', or 0, 1, or -1.' 
%Author: Ji Lin, 2007
if nargin<4 tail=0;end 
if nargin<3 a=0.05;end 
n1=length(X);n2=length(Y); 
f=var(X)/var(Y); 
if tail == 0 % two-tailed test 
    f1=finv(1-a/2,n1-1,n2-1);f2=finv(a/2,n1-1,n2-1); 
    if (f1<= f)|(f<=f2) 
        h = '拒绝H0'; 
    else 
        h = '接受H0'; 
    end 
elseif tail == 1 % right one-tailed test 
    f1 = finv(1-a,n1-1,n2-1); 
    if chi21<= chi2 
        h = '拒绝H0'; 
    else 
        h = '接受H0'; 
    end     
elseif tail == -1 % left one-tailed test 
    f1 = finv(a,n1-1,n2-1); 
    if f<= f1 
        h = '拒绝H0'; 
    else 
        h = '接受H0'; 
    end 
else 
    error('stats:ftest:BadTail',... 
          'TAIL must be ''both'', ''right'', or ''left'', or 0, 1, or -1.'); 
end