This chapter considers various parameters for testing a single population. It presents a number of mechanical joint design-studies, and their analyses, to illustrate the use of the aforecited statistical procedures. The chapter considers a methodology for hypothesis testing of two different populations or distributions. It presents a small number of design studies focusing on the analysis of two population means. The irregular shape of the ends would cause different answers to be obtained depending on just where the measurements were taken. A more common reason for obtaining a spread of readings in a series of observations is that the item being measured is not sharply defined. Dorf Motors, a vehicle manufacturer, is interested in performing a fastener integrity reliability study of their vehicles. A fastener tool lab conducts a study to compare the amount of powder coating of dry thread adhesive applied to prevailing torque fasteners from two different manufacturers.