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chi2test

version 1.0.0.0 (1.93 KB) by Peder Axensten
The chi-squared test.

25 Downloads

Updated 30 Aug 2007

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Usage: [p, Q]= chi2test(x)

The chi-squared test.

Given a number of samples this function tests the hypothesis that the samples are
independent. If Q > chi2(p, nu), the hypothesis is rejected.

Each column represents a variables, each row a sample.

If you find any errors, please let me know: .

ARGUMENTS:
x Absolut numbers.
p The prob ability value, calculated from Q.
Q The resulting Q-value.

EXAMPLE 1
In region A, 324 of 556 cows were red, whereas in region B 98 of 260 were red.
[p, Q]= chi2test([324, 556-324; 98, 260-98])
p= 4.2073e-08
Q= 30.0515
With an error risk of about 4e-08, we can claim that the samples are independent.

EXAMPLE 2
Throw two different dices to see if they have the same probability of 1 (and 2, 3, 4, 5, 6).
We don't check if they are symetrical, only if the both behave in the same way.
[p,Q] = chi2test([15,10; 7,11; 9,7; 20,15; 26,21; 19,16])
p= 0.8200
Q = 2.2059
The dices don't significantly behave differently. That is, they seem to behave in the same way.

HISTORY: v.1.0, first working version, 2007-08-30.

COPYRIGHT: (c) 2007 Peder Axensten. Use at own risk.

Cite As

Peder Axensten (2021). chi2test (https://www.mathworks.com/matlabcentral/fileexchange/16177-chi2test), MATLAB Central File Exchange. Retrieved .

Comments and Ratings (3)

Marius Marinescu

Sorry, the last comment is not to this post. Please ignore or remove it. Thanks.

Wilma

yang

ths for your teaching.

MATLAB Release Compatibility
Created with R2007a
Compatible with any release
Platform Compatibility
Windows macOS Linux
Acknowledgements

Inspired: Statistical Analysis, wavelet transform of image

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