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11 Jun 2012 (Updated )

Welch ANOVA Test for Unequal Variances.

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The ANOVA F-test to compare the means of k normally distributed populations is not applicable when the variances are unknown, and not known to be equal. A spacial case, k=2, is the famous Behrens-Fisher problem (Behrens, 1929; Fisher, 1935). Welch (1951) test was proposed to fill this void, a generalization to his 1947 previous paper (Welch, 1947).

Syntax: function welchanova(x,alpha)

x – data nx2 matrix (Col 1 = data; Col 2 = sample code)
alpha - significance level (default=0.05)

- Summary statistics from the samples
- Decision on the null-hypothesis tested

Required Products Statistics and Machine Learning Toolbox
MATLAB release MATLAB 7.10 (R2010a)
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Comments and Ratings (2)
02 Mar 2015 Hugo Mendonça

I am just wondering if it is possible to use your program as 2-way anova for unequal variances?

Comment only
21 May 2014 gargouri

I had used your code of Levene test :)
and I found that samples have not an homogenious variance so I can not use ANOVA.
So I would like to know instead of ANOVA if we can use Welch ANOVA since the distribution not normal?
Thank you

11 Jun 2012 1.1

It was added an appropriate format to cite this file.

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