Assessing psychology students’ difficulties in elementary variance analysis

In this paper we present a study directed to assess the students’ difficulties in understanding elementary variance analysis. Responses from 224 undergraduate psychology students who had previously studied this topic to a questionnaire are analysed. Contents of the questionnaire include the selection of a variance analysis model, understanding of assumptions and the associated linear model in this procedure, the computations involved in variance analysis and the interpretation of results. While the understanding of computations, the selection of the model, and the understanding of the decomposition of the variance in the linear model were easy, the students had difficulties in understanding the assumptions of variance analysis and in interpreting the results in the problem context. These results provide information in an area where little prior research is available.