Compile Error on Final Arrays Project

Question

I'm sure this is an elementary problem, but I'm relatively new to Java. Can someone glance at this code for any apparent errors. I'm pretty sure the fillArrays() method and average() method are correct. I've tried everything, and there's no one I can ask. Any help would be greatly appreciated. This program is the final project of my java programming intro class.
Thanks
import ann.easyio.*;
public class DoubleArrayOps
public static double[] subArray(double data[], int start, int stop)
double newData[] = new double[stop-start+1];
int storeAt = 0;
for (int i = start; i<= stop; i++)
newData[storeAt++] = data;
return newData;
public static void printArray(Screen out, double data[])
for (int i = 0; i< data.length; i++)
out.print(data[i] + " ");
public double average(double [] scoreArr)
int numValues = scoreArr.length;
double sum = 0.0;
for(int i = 0; i < numValues; i++)
sum += scoreArr[i];
if(numValues > 0)
return (sum / numValues);
else
System.err.println();
return 0.0;
public double standardDev(double [] scoreArr)
int numValues = scoreArr.length;
if(numValues > 0)
double avg = average(scoreArr);
double sumSqrTerms = 0.0;
double term;
for(int i = 0; i < numValues; i++)
term = (scoreArr[i] - avg);
Math.pow(term,2) += sumSqrTerms;//Compile error.
return(Math.sqrt(sumSqrTerms / numValues));
else
System.err.println();
return 0.0;
import ann.easyio.*;               
import hoj.*;
class Grades extends Object
static Screen theScreen = new Screen();
static Keyboard theKeyboard = new Keyboard();
public static void main(String args[])
String [] nameArr;
double [] scoreArr = new double [1000];
double scores = fillArrays( nameArr, scoreArr);
scoreArr = DoubleArrayOps.subArray(scoreArr, 0, scores-1);
theScreen.print( "\nMean score: "
+ DoubleArrayOps.average(scoreArr)
+ "\n"
+ "Std. Dev: "
+ DoubleArrayOps.standardDev(scoreArr)
+"\n");
char [] gradeArr;
gradeArr = computeLetterGrades(scoreArr);
displayArrays( nameArr, scoreArr, gradeArr);
public static double fillArrays(String [] nameArr, double [] scoreArr)
int n = 0;
String name;
double score;
while(true)
Keyboard theKeyboard = new Keyboard();
theScreen.print("\nPlease enter students name: ");
name = theKeyboard.readWord();
if (name.equals("done"))
          break;
nameArr[n]=name;
score = theKeyboard.readDouble();
scoreArr[n]=score;
n += 1;
return n;
public static char computeLetterGrades(double [] scoreArr)
int numValues = scoreArr.length;
char [] gradeArr = scoreArr.length;
if(numValues > 0)
     double avg = average(scoreArr);
          double sDev = standardDeviation(scoreArr);
          double F_CUT_OFF = (avg - 1.5 * standardDev);
          double D_CUT_OFF = (avg - 0.5 * standardDev);
          double C_CUT_OFF = (avg + 0.5 * standardDev);
          double B_CUT_OFF = (avg + 1.5 * standardDev);
for(int i = 0; i < numValues; i++)
          if(scoreArr < F_CUT_OFF)
          return gradeArr['F'];
          else if(scoreArr < D_CUT_OFF)
          return gradeArr['D'];
          else if(scoreArr < C_CUT_OFF)
          return gradeArr['C'];
          else if(scoreArr < B_CUT_OFF)
          return gradeArr['B'];
          else
          return gradeArr['A'];
          return gradeArr[];
public static double displayArrays(String [] nameArr, double [] scoreArr, char [] gradeArr)
Screen theScreen = new Screen();
theScreen.print(+ Grades.fillArrays(nameArr,scoreArr)
+ Grades.computeLetterGrades(gradeArr);

Answer 1

All my errors are compile errors. Here are the errors I get, and I've tried everything I know with null results. :) Thanks for the responses!
Grades.java:115: 'class' or 'interface' expected
public static char computeLetterGrades(double [] scoreArr)
^
Grades.java:31: subArray(double[],int,int) in DoubleArrayOps cannot be applied to (double[],int,double)
scoreArr = DoubleArrayOps.subArray(scoreArr, 0, scores-1);
^
Grades.java:34: non-static method average(double[]) cannot be referenced from a static context
+ DoubleArrayOps.average(scoreArr)
^
Grades.java:37: non-static method standardDev(double[]) cannot be referenced from a static context
+ DoubleArrayOps.standardDev(scoreArr)
^
Grades.java:42: cannot resolve symbol
symbol : method computeLetterGrades (double[])
location: class Grades
     gradeArr = computeLetterGrades(scoreArr);
^
Grades.java:44: cannot resolve symbol
symbol : method displayArrays (java.lang.String[],double[],char[])
location: class Grades
     displayArrays( nameArr, scoreArr, gradeArr);
^
DoubleArrayOps.java:69: unexpected type
required: variable
found : value
          Math.pow(term,2) += sumSqrTerms;//Compile error.