Question 188:

Asked on May 12, 2008

Tags: Unequal Sample Size , Chi-Square

1

Answer:

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Files Available For Download

1. Q188_1_q188ChiSquare.xls

For Chi-square analysis, the sample sizes do not need to be equal. If your sample size is small, it will affect the computation. If you need help with the computations of a Chi-Square.  I've attached an example of a Chi-Square test of Independence with unequal sample sizes in excel so you can see the computations.

In general, the formula is 

Sum of       (O-E)²
                 ---------
                     E

• O means the observed frequencies
• E means the expected frequencies

and this is done for each cell. See the attached excel file as well as the hyperstat article