Exact Tests on Counts

 

Menu location: Analysis_Exact

• Sign test
• Fisher's exact test for 2 by 2 tables
• Generalised Fisher's exact and chi-square tests for r by c tables
• Matched pairs (McNemar, Liddell)
• Confidence limits for 2 by 2 odds
• Confidence limits for Poisson rates and counts

 

This section provides permutational probabilities and exact confidence limits for various counts and tables. Other sections such as nonparametric also employ exact methods.

 

Please note that exact methods are more appropriate than large sample methods for dealing with small numbers, but they are not a substitute for collecting larger samples. You should always aim to collect the largest sample that it is practical to obtain.

 

Exact refers to the precision of the statistical method given perfect data and not to the quality of the results - largely dependent upon how good your experiment was.