The study seeks to determine the robustness and power of parametric analysis of covariance and analysis of covariance using rank transformation to violation of the assumption of normality. The study employs a Monte Carlo simulation procedure with varying conditions of population distribution, group size, equality of group size, scale length, regression slope, and Y-intercept. The procedure was performed on raw data and ranked data with untied ranks and tied ranks.

The problem considered involved assessing willingness of educators to participate in a study offering monetary incentives. Determination of willingness was implemented by sending educators a packet requesting return of a postcard to indicate willingness to participate. The purpose was twofold: to determine the effect of a monetary incentive upon willingness of educators to participate in a research study, and to analyze implications for mail questionnaire studies. A sample of 600 educators was chosen from directories of eleven public schools in north Texas. It included equal numbers of male and female teachers and male and female administrators. Subjects were assigned to one of twelve groups. No two from a school were assigned to different levels of the inducement variable.