What are the assumptions of a two-way ANOVA?

Your data must meet the following assumptions when performing two-way ANOVA:

• There is homogeneity of variance (the population variations around the mean for each group being compared are similar among all groups). 
• The independent variables are not dependent on one another. All samples are independent (chosen at random and on their own).  
• The dependent variable represents unique observations (observations are not grouped within individuals or locations). 
• Groups have equal sample sizes.