The mitigation of outliers serves to increase the strength of a relationship between variables. This study defined outliers in three different ways and used five regression procedures to describe the effects of outliers on 50 data sets. This study also examined the relationship among the shape of the distribution, skewness, and outliers.

The purpose of this study was to investigate the effects of supplemental on-task and performance contingencies on the acquisition of math skills for elementary school children identified as seriously emotionally disturbed/behaviorally disordered, attention deficit disordered, and students without disabilities. Three experimental conditions were utilized, involving teacher-directed instruction with (a) no contingencies, (b) contingencies for academic performance, and (c) contingencies for academic performance and on-task behavior. The study was designed to measure the effects of these contingency conditions on the number of math problems solved accurately by the study's participants.