Fisher Exact Probability Test: 2x4
This unit will perform the Freeman-Halton extension of the Fisher exact probability test for a two-rows by four-columns contingency table, providing that the total size of the data set is no greater than N=120. The test will yield two probability values, PA and PB, defined as follows:
 PA = the probability of the observed array of cell frequencies plus the sum of the probabilities of all other cell-frequency arrays (such as would be consistent with the observed marginal totals) that are equal to or smaller than the probability of the observed array. PB = the probability of the observed array of cell frequencies plus the sum of the probabilities of all other cell-frequency arrays (such as would be consistent with the observed marginal totals) that are smaller than the probability of the observed array. Note that PA and PB are both non-directional (two-tailed) probabilities.

A chi-square test will also be performed on the data set, providing that at least 80% of the cells have an expected frequency of 5 or greater, and that no cell has an expected frequency smaller than 1.0.

Data Entry
 C1 C2 C3 C4 Totals The Fisher test is performed only if N≤120. Note that PA and PB are both non-directional (two-tailed). The chi-square test is performed only if at least 80% of the cells have an expected frequency of 5 or greater, and no cell has an expected frequency smaller than 1.0. R1 R2 Totals Fisher Exact Probability Test Probability per Definition A: PA = Probability per Definition B: PB = No. of tables evaluated = Chi-Square Test (df=3) Chi-square = P =

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