private static void average(int... amount) {
    double average = (double) amount[0];
    for (double i = 1; i < amount.length; i++) {
        System.out.printf("average: %d%n", (int) average);
        double newWeight = (i + 1d) / i;
        double newAverage = average / newWeight;
        double thisAverage = (amount[(int)i]) / (i+1d);
        average = newAverage + thisAverage;
    }
    System.out.printf("average: %d%n", (int) average);
}

public void test(int[] values) {
    BigDecimal sum = BigDecimal.ZERO;
    for (int count = 0; count < values.length; count++) {
        sum = sum.add(new BigDecimal(values[count]));
        System.out.printf("%s/%d = %s%n", sum, (count+1), sum.divide(new BigDecimal(count+1)));
    }
}