question: public static double sumOfMeanDifferencesOnePoint ( double [ ] vector ) { double mean = sum ( vector ) / vector . length ; double ret = 0 ; for ( int i = 0 ; i < vector . length ; i ++ ) { double vec1Diff = Math . pow ( vector [ i ] - mean , 2 ) ; ret += vec1Diff ; } return ret ; }
target:  Used for calculating top part of simple regression for beta 1