XXXIV. The other side of ‘statistical significance’: alpha, beta. delta, and the calculation of sample size

Abstract

‘Statistical significance’ is commonly tested in biologic research when the investigator has found an impressive difference in two groups of animals or people. If the groups are relatively small, the investigator (or a critical reviewer) becomes worried about a statistical problem. Although the observed difference in the means or percentages is large enough to be biologically (or clinically) significant, do the groups contain enough members for the numerical differences to be ‘statistically significant’?