has part preceded by is about has_specified_input has_specified_output achieves_planned_objective has value study design independent variable study design dependent variable data transformation ANOVA normal distribution hypothesis two-way ANOVA true 1 2 true Orlaith Burke Alejandra Gonzalez-Beltran Philippe Rocca-Serra STATO http://courses.statistics.com/software/R/Rtwoway.htm two factor ANOVA two-way anova is an analysis of variance where the different groups being compared are associated the factor levels of exatly 2 independent variables. The null hypothesis is an absence of difference between the means calculated for each of the groups. The test assumes normality and equivariance of the data. homoskedasticity hypothesis number of degrees of freedom Levene's test Barlett's test Brown Forsythe test Kolmogorov-Smirnov test F-test standardized mean difference confidence interval residual continuous variable categorical variable between group comparison objective root-mean-square standardized effect ready for release