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Chi-square test - contingency tables

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Chi-square test - contingency tables

by Panagiotis Moulos

 

11 Feb 2008 (Updated 11 Feb 2008)

This function performs the chi-square test for 2x2 contingency tables

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Description

CHISQUARECONT takes as input a 2x2 matrix that represents a 2x2 contingency table and
calculates the probability of obtaining the observed and each of the more extreme tables
based on the pearson chi square test which is based on the chi square distribution. The
chi square test might become unreliable when the total number of expected frequencies
(cell values in the contingency table) are not large enough (the total is smaller than
20 or a cell contains a value lower than 5). In such cases, the Fisher exact test should
be used instead.

Usage : p = chisquarecont(contab)
        [p,x2] = chisquarecont(contab)

Input : contab -> a 2x2 contigency table created from the frequency data
Output : p -> The p-value of the test (the probability of obtaining the observed
                   and each of the more extreme tables)
         x2 -> The value for the chi square statistic

For an example, see help inside the file.

Required Products Statistics Toolbox
MATLAB release MATLAB 7.1.0 (R14SP3)
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Tag Applied By Date/Time
statistics Panagiotis Moulos 22 Oct 2008 09:47:25
probability Panagiotis Moulos 22 Oct 2008 09:47:25
chi square Panagiotis Moulos 22 Oct 2008 09:47:25
contingency table Panagiotis Moulos 22 Oct 2008 09:47:25
frequency Panagiotis Moulos 22 Oct 2008 09:47:25

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