Fisher's exact test of 2x3 contingency tables permits calculation of precise probabilities in situation where, as a consequence of small cell frequencies, the much more rapid normal approximation and chi-square calculations are liable to be inaccurate. The Fisher's exact test involves the computations of several factorials to obtain the probability of the observed and each of the more extreme tables. Factorials growth quickly, so it's necessary use logarithms of factorials. This computations is very easy in Matlab because x!=gamma(x+1) and log(x!)=gammaln(x+1). This function is fully vectorized to speed up the computation.
Syntax: p=myfisher23(x)

Inputs:
X - 2x3 data matrix
Outputs:
- Three p-values

Created by Giuseppe Cardillo
giuseppe.cardillo-edta@poste.it

To cite this file, this would be an appropriate format: Cardillo G. (2007) MyFisher23: a very compact routine for Fisher's exact test on 2x3 matrix http://www.mathworks.com/matlabcentral/fileexchange/15399