ODA vs. t-Test: Lysozyme Levels in the Gastric Juice of Patients with Peptic Ulcer vs. Normal Controls

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.

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