Robert M. McFatter Psychology 415- Experimental Psychology II Basic Principles in the Design and Evaluation of Experiments

The interpretation of statistical analyses of data derived from a study may be carried out at several levels. At one level, the results may be interpreted simply as evidence addressing questions such as whether there are differences among the means of several populations or whether the variables appear to demonstrate various kinds of associations among themselves. For this level of interpretation, statistical assumptions (e.g., normality, homogeneity of variance, etc.) may well be the primary considerations. Often, however, the analyst wishes to draw conclusions about causal processes, mechanisms of action, etc. Interest in these kinds of inferences is common in scientific investigations. It is important in thinking about the interpretation of any set of data to consider the natur