ttest0.m

统计学习的Matlab程序:包括各种假设检验,模型识别和线性回归等.

function [h,p,t,t1]=ttest0(X,m,a,tail)
%TTEST0 单个正态总体均值的假设检验（t检验）
%参考文献：《应用数理统计》（叶慈南编） p114.
%TTEST  One-sample and paired-sample T-test.
%调用格式：[h,p,t,t1]=ttest0(X,m,a,tail)
%X为样本，m为检验均值，a为显著性水平
%TAIL must be ''both'', ''right'', or ''left'', or 0, 1, or -1.'

%By：Ji Lin
%Email: [e-mail]
%Blog: http://linji526.spaces.live.com
%Date: 2007，2008/08/18

if nargin<4 
    tail=0;
end
if nargin<3 
    a=0.05;
end

n=length(X);
t=(mean(X)-m)*sqrt(n)/std(X);
if tail == 0 % two-tailed test
    t1=tinv(1-a/2,n-1);
    p=1-2*tcdf(t,n-1);
elseif tail == 1 % right one-tailed test
    t1 = tinv(1-a,n- 1);
    p =1- tcdf(t, n - 1);        
elseif tail == -1 % left one-tailed test
    t1 = tinv(a,n - 1);
    p = tcdf(t, n - 1);
else
    error('stats:ttest:BadTail',...
          'TAIL must be ''both'', ''right'', or ''left'', or 0, 1, or -1.');
end
% Determine if the actual significance exceeds the desired significance
if p <= a
    h = '拒绝H0';
elseif p > a
    h = '接受H0';
else % isnan(p) must be true
    h = NaN;
end