The article discusses how to compare the means of three or more groups using a statistical tool called analysis of variance (ANOVA). ANOVA helps determine if there is a significant difference between the means of different groups and can also test for interactions between factors that may affect outcomes. The study explains the process of calculating one-way and two-way ANOVA by hand using hypothetical scenarios from Radiation Oncology. It also introduces concepts like repeated measures ANOVA, analysis of covariance (ANCOVA), multiple analyses of variance (MANOVA), and factorial ANOVA.