ABSTRACT
<p><b>OBJECTIVE</b>To accomplish the computation of Fisher exact probability test for fourfold table data in Excel.</p><p><b>METHOD</b>The computing program of exact probability method for medical data in fourfold table design was edited by employing the IF statement and the relevant functions, such as SUM, FACT, DSUM, etc in Excel. The computational results are compared and evaluated according to the case studies.</p><p><b>RESULTS</b>The output of Fisher Exact Probability was generated and presented correctly following the input of four numerical values into the computation program in the setting of Excel. The parametric outcomes are in agreement with those produced by SAS and SPSS, in the combination tables containing the P value, two-tailed cumulative P value, left-tailed P-value, right-tailed P-value, Chi2 values and P values both for direct Chi-squared test and corrected Chi-squared test.</p><p><b>CONCLUSIONS</b>Direct Chi-squared test, corrected Chi-squared test combined with Fisher Exact Probability test for fourfold table data can be conveniently, rapidly, and accurately accomplished in Excel.</p>