question: public static float mean ( float [ ] data , int startIndex , int endIndex ) { float mean = 0 ; int total = 0 ; startIndex = Math . max ( startIndex , 0 ) ; startIndex = Math . min ( startIndex , data . length - 1 ) ; endIndex = Math . max ( endIndex , 0 ) ; endIndex = Math . min ( endIndex , data . length - 1 ) ; if ( startIndex > endIndex ) startIndex = endIndex ; for ( int i = startIndex ; i <= endIndex ; i ++ ) { if ( Float . isNaN ( data [ i ] ) ) throw new IllegalArgumentException ( "NaN not allowed in mean calculation" ) ; mean += data [ i ] ; total ++ ; } mean /= total ; return mean ; }
target:  Compute the mean of all elements in the array. No missing values (NaN) are allowed.