We learned at the outset of the semester some differences between Variance and Standard Deviation. One important difference is that variances (of independent variables) can be effectively added together to yield new information about the combination, while standard deviations cannot. We're used to taking the square root of the Variance to get the Standard Deviation, although in ANOVA we don't do that. Instead, we apply a Degree of Freedom to find a Mean Squared.

Discuss how and where the adding of Variance concept is being used in the ANOVA technique, and then discuss what is being described by the Mean Squares being calculated.