The standard sum of squares as I know it is:
where m is the mean. I ran into a different one which can be written two ways:
Σ(X2) - (ΣX)2/n = Σ(X2) - m ΣX
I believe the latter is called the "correction term for the mean" (e.g. here). My algebra seems to be inadequate to show these are equivalent, so I was looking for a derivation. Thanks.