import java.text.DecimalFormat;

public class Work2_3
{
	public static void main(String[] args)
	{
		DecimalFormat f2 = new DecimalFormat("0.00");

		double[] test1 = {3, 5, 4, 3, 1, 7};
		double x = DoCal(test1, test1.length);
		System.out.println("x = " + f2.format(x));
		// x  = 3.833333
	}
	//------------------------
	private static double DoCal(double[] test, int size)
	{
		double s = 0;
		for(int i=0; i<size; i++)
			s += test[i];
		return s/size;
	}
}