math.statistics: Add sum-of-squares word, add sum-of-squared-errors/sum-of-absolute-errors words.
math.statistics: Add sum-of-squares word, add sum-of-squared-errors/sum-of-absolute-errors words.

mcandre/factor,mcandre/factor,mcandre/factor,mcandre/factor,mcandre/factor,mcandre/factor,mcandre/factor