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welchanovawd

version 1.3 (3.3 KB) by

Welch ANOVA Test for Unequal Variances without data.

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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).

This m-file works without all the data samples. But only with the size, mean and variance samples.

Syntax: function welchanova(x,alpha)

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

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

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Updates

1.3

We improve the code. Thanks to Dr. Jürgen Kayser, Department of Psychiatry, Columbia University Research Scientist, Cognitive Neuroscience, New York State, who suggest us to remove a bug.

1.1

It was added an appropriate format to cite this file.

MATLAB Release
MATLAB 7.10 (R2010a)

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