How we change what others think, feel, believe and do

McNemar's Q

Description

This test is used when there is dichotomous data (two-state, eg. yes/no) in table format. It is used to test for correlation.

A typical arrangement is for multiple questions being asked of multiple people.

Provided N (the number of individuals) is larger than 30, the statistic follows the Chi-square distribution and the Chi Square table can be used.

Q is calculated as:

Q = ((C-1)*(SUM(T²) - (SUM(T))²) / (C*SUM(X) - SUM(X²))

...where T is the total for each column, X is the total for each row, and C is the number of questions.

This is a variant on the chi-square test to cope with situations where variables can only have one of two values.