Paul R. Yarnold

Optimal Data Analysis, LLC

Lysozyme levels in gastric juice of peptic ulcer patients were compared against normal controls by *t*-test, finding *p*<0.05. Because standard deviations differed by a factor of two between groups, and were proportional to the means, analysis of natural logarithms was instead deemed appropriate: the resulting *t*-test wasn’t statistically significant. Analyzed by ODA no statistically significant between-group difference emerged, and results obtained for raw data and for natural logarithms were identical because ODA results (i.e., *p* and ESS) are invariant over all monotonic transformations of the data.