Studies in the Design and Analysis of Dental Experiments. 7. Non-parametric Tests (Correlated Samples with Ordinal Scales)
SHIRLEY STERNBERG 1,
JOHN W. FERTIG 1, and
NEAL W. CHILTON 1
1 School of Public Health and Administrative Medicine of the Faculty of Medicine, Columbia University, New York, New York
Two tests for correlated samples with ordinal measurements have been described: the Sign Test for two correlated samples and the Friedman method of ranks for more than two correlated samples. The tests were illustrated with data consisting of P-M-A scores of a group of patients before and after use of a dentifrice and caries extent scores of rats using three different diets, respectively. An analysis-of-variance approach has been described that facilitates the calculation of appropriate significance tests.
Submitted on June 12, 1962
