Can somebody please tell me what the mean total sum of squares is, and how you calculate it?

Thanks!

Can somebody please tell me what the mean total sum of squares is, and how you calculate it?

Thanks!

It’s a variance. Depending on the variable you’re estimating the variance for, the degrees of freedom (denominator) can vary. Where did you see this, and what was the context?

SST = sum of squares total = the total variation

RSS = residual sum of squares = the explained variation

SSE = sum of squares error = the unexplained variation

SST = RSS + SSE

total variation = explained variation + unexplained variation

Keep in mind, the OP asked for the ** mean** SST (variance of Y, if using a regression)-- total variation and variance are not the same thing (even if it sounds like it). Also, “RSS” stands for _