McNemarextest

McNemar's Exact Test.

This m-file performs the conditional as well as the Chi-squared corrected for discontinuity McNemar's exact test for two dependent (correlated) samples that can occur in matched-pair studies with a dichotomous (yes-no) response. Dependent samples can also occur when the same subject is measured at two different times. It tests the null hypothesis of marginal homogeneity. This implies that rows totals are equal to the corresponding column totals. So, since the a- and the d-value on both sides of the equations cancel, then b = c. This is the basis of the proposed test by McNemar (1947). The McNemar test tests the null hypothesis that conditional on b + c, b has a binomial (b + c, 1/2) distribution.

The proper way to test the null hypothesis is to apply the one-sample binomial test. If there is no association between b and c values, then the probability is 0.5 that the sample 1 and sample 2 pair falls in the
upper-right cell and 0.5 that it falls in the lower-left cell, given that the pair falls off the main diagonal.

File needs to input data vector defined by the observed frequency cells [a,b,c,d], desired test [t = 1, one-tail; t = 2, two-tail (default)], and significance level (default = 0.05).

It outputs a table with the proportion of success for the dependent samples and the P-value.