Two-Way ANOVA
Candlefocus EditorUnlike a one-way ANOVA that looks at the effect of a single variable on the dependent variable, a two-way variant considers the interaction between the two independent variables and the dependent variable. Two-way ANOVA requires that data needs to be collected from all possible combinations of variable values to determine the relationship between the independent and dependent variables.
Two-way ANOVA is widely used in multiple research areas such as sociology, psychology, economics and engineering, as well as in hypothesis testing. It can be used to determine how factors such as setting (location, time), treatment options, and demographic characteristics interact with one another to affect an endpoint, such as weight loss.
In general, running a two-way ANOVA involves testing a null hypothesis that says there is no difference between the groups of interest. If there is a significant difference between the groups, then the hypothesis is rejected, and the results of the two-way ANOVA provide insight into which factor (or combination of factors) had the most impact on the outcome.
Two-way ANOVA yields several important metrics related to the effect of the independent variables, such as the F ratio, which compares the variation seen between the groups in the experiment to the total variation. Another metric is the eta-square (η^2), which represents the proportion of variance accounted for in the outcome. The multivariate version of ANOVA (MANOVA) can also be used to interpret the effects of multiple dependent variables.
Two-way ANOVA is a powerful tool for analyzing the relationships between two or more variables and for making predictions about how changes in the independent variables might affect a given outcome. It is a good resource for researchers who need to measure both the overall effects of multiple variables and the interaction effects between them, allowing them to draw meaningful conclusions from the analysis.