This paper describes some of the situations in which a psychologist is likely to violate the assumption of independent errors. A Monte-Carlo study of the effects of this violation is then described. A number of examples of different kinds and degrees of dependency are included along with a table that gives the effect of the dependency upon the shape of the test statistic's distribution. The results of this study demonstrate that this assumption is a critical one. Researchers are strongly urged to avoid hypothesis testing if they suspect that the assumption of independence has been violated.
Get full access to this article
View all access options for this article.
References
1.
Boneau, C. A.The effects of violations of assumptions underlying the t-test. Psychological Bulletin , 1960, 57, 49-64.
2.
Box, G. E. P.Some theorems on quadratic forms applied in the study of analysis of variance problems, II. Effects of inequality of variance and of correlation between errors in two-way classification. Annals of Mathematical Statistics, 1954, 25, 484-498.
3.
Cochran, W. G.Some consequences when the assumptions for the analysis of variance are not satisfied. Biometrics, 1947, 3, 22-38.
4.
Glass, G. V, Peckham, P. D., and Sanders, J. R.Consequences of failure to meet assumptions underlying the analysis of variance and covariance. Review of Educational Research, 1972, 42, 237-288.
5.
Huber, P. J.Robust statistics: a review. The Annals of Mathematical Statistics, 1972, 43, 1041-1067.
6.
Johnston, J.Econometric methods. New York: McGraw-Hill, 1972.
