Relation between the shape of population distribution and the robustness of four simple test statistics

SUMMARY The underlying theory upon which a great number of statistical procedures are based assumes that the variable or variables sampled are normally distributed. While there has been a good deal of theoretical research on the robustness of these procedures, the results seem not to have been set out in terms which the unsophisticated user of statistical methods can easily assimilate. The present paper, based on extensive computer simulation, aims at relating diagrammatically the shape of population to the robustness of the distribution of