Many are the pitfalls which may be encountered during the preparation of a statistical survey. Erroneous conclusions drawn from the misinterpretation of statistical data have appeared many times in medical literature and more than once these mistaken concepts have been quoted for years by subsequent writers.
I should like to call attention to some of the conclusions drawn by Lincicome, Thiede and Carpenter in an article entitled “An Evaluation of the Influence of World War II on the Incidence of Amebiasis,” which appears in the American Journal of Tropical Medicine for March, 1950. In Table I the authors compile a total of 50,517 persons examined for the presence of amebiasis by many different investigators. The percentage incidence of infestation with Endamoeba histolytica is given for each reported series. The authors of this article then compute the average of the column of numbers listed as the percentage incidence of infection in each series.