question: public static double rootMeansSquaredError ( double [ ] real , double [ ] predicted ) { double ret = 0.0 ; for ( int i = 0 ; i < real . length ; i ++ ) { ret += Math . pow ( ( real [ i ] - predicted [ i ] ) , 2 ) ; } return Math . sqrt ( ret / real . length ) ; }
target:  This returns the root mean squared error of two data sets