We would be testing the simple H 0 : µ Enriched = µ Standard. For instance, we could put 40 mice into a single factor experiment, with 20 exposed to enriched housing and 20 exposed to standard housing. Schematically, the design would look like the table below: Enriched Standard Housing Housing Ad Lib Feeding n = 10 n = 10 Once a Day Feeding n = 10 n = 10 Of course, we could conduct two separate experiments with our 40 mice (or think of this experiment as two separate one-way independent groups analyses). Likewise, of the 20 mice in the standard housing, 10 are fed ad lib and 10 are fed once a day. Of the 20 mice assigned to the enriched housing, 10 are fed ad lib and 10 are fed once a day. Of the 40 mice in the experiment, 20 are randomly assigned to the enriched housing and 20 are assigned to the standard housing. Thus, this experiment is a 2x2 independent groups design, which means that there are 4 unique conditions to the experiment. In this experiment, the housing factor can take on two levels (enriched or standard) and the feeding schedule can take on two levels (ad lib or once a day). 182 ff.), an experimenter is interested in assessing the impact of housing (the first factor) and feeding schedule (the second factor) on errors made in running a maze (the dependent variable). The sort of experiment that produces data for analysis by a two-factor ANOVA is one in which there are two factors (independent variables). 9, so be sure to read that chapter carefully. Important background information and review of concepts in ANOVA can be found in Ray Ch. 1 Two-Way Analysis of Variance (ANOVA) An understanding of the one-way ANOVA is crucial to understanding the two-way ANOVA, so be sure that the concepts involved in the one-way ANOVA are clear.