Now, if the two factors in the study (practice and stress) interact, this means that the effect of one factor depends on the level of the other factor. Let's insert some data to see if there is an interaction in this study.The table above indicates the cell means, as well as the marginal means and the grand mean, for the study. For example, the mean number of words recalled under the low stress, one practice condition is 8. This is a cell mean.herefore, we have evidence of an interaction in this study. Of course, you will need to carry out the appropriate statistical test before you can conclude that your evidence is strong enough to support the claim that there is an interaction in the population.