Specifically, . A linear model was constructed after checking that the data satisfied all linear model assumptions: normality of residuals, constant variance of errors, and no serial correlation. According to Smith’s experiment, “The three least painful locations were the skull, middle toe tip, and upper arm (all scoring a 2.3) and the three most painful locations were the nostril, upper lip, and penis shaft”. An estimate as to why this is the case was offered by Smith, but not confirmed, to be the thickness of the skin. It seems the results bode well to this assumption due to the fact that the skin is thinnest on the genitals and the thickest on the skull. An assumption like this is hard to make, though, considering the main flaw in this experiment. The fact that there was only one test subject used during the entire experiment is probably the biggest flaw that it exhibits. In order to make these results more substantial, it is crucial to conduct the methods on many different test