ttest2u
Purpose
Two sample t-test (assuming unequal variance).
Synopsis
result = ttest2u(x,y,test,dfapp)
Description
Calculates a two sample t-test for samples (x) and (y)
assuming unequal variance.
Inputs:
x
= matrix (column vector) in which the sample data is stored.
y
= matrix (column vector) in which the sample data is stored.
ttest
= [-1,{0},1] indicates what ttest is for:
-1 - lower
tail H0: mean(x) <= mean(y)
0 - wo-tail H0:
mean(x) ~= mean(y) {default}
1 - upper
tail H0: mean(x) >= mean(y)
dfapp
= [{-1}, 1] indicates which degree of freedom calculation to use.
-1 - indicates Welch's
approximate degrees of freedom {default}
1 - indicates
Satterthwaite's approximate degrees of freedom
Outputs:
The output (result) a structure with the following fields:
t
= test statistic.
p
= probability value
mean1
= mean of x
mean2
= mean of y
var1
= variance of x
var2
= variance of y
n1
= length of x
n2
= length of y
pse
= pooled standard error
df
= degress of freedom
app
= 'Satterthwaite' or 'Welch'
hyp
= hypothesis being tested
Examples
result = ttest2u(x,y);
result = ttest2u(x,y,test);
result = ttest2e(x,y,test,dfapp);
See Also
ttest1, ttest2e, ttest2p
