Java计算上下基线

public class GetAverageandStandardDevition {
	static List<Long> list = new ArrayList<Long>();
	static {
		list.add(3210981L); // 1
		list.add(3210881L); // 2
		list.add(3210781L); // 3
		list.add(3210681L); // 4
		list.add(3210581L);
		list.add(3210481L);
		list.add(3210381L);
		list.add(3210281L);
		list.add(3210181L);
		list.add(3210081L);
		list.add(3219981L);
		list.add(3218981L);
		list.add(3217981L);
		list.add(3216981L);
		list.add(3215981L);
		list.add(3214981L);
		list.add(3213981L);
		list.add(3212981L);
		list.add(3211981L);
		list.add(3220981L);
		list.add(3230981L);
		list.add(3240981L);
		list.add(3250981L);
		list.add(3260981L);
		list.add(3270981L);
		list.add(3280981L);
		list.add(3290981L);
		list.add(3210982L);
		list.add(3210983L);
		list.add(3210984L);
		list.add(3210985L);
		list.add(3210986L);
		list.add(3210987L);
		list.add(3210988L);
		list.add(3110989L);
		list.add(3210981L);
		list.add(3310981L);
		list.add(3410981L);
		list.add(2510981L);
	}

	// 獲取平均值
	public double getAverage() {
		int sum = 0;
		for (int i = 0; i < list.size(); i++) {
			sum += list.get(i);
		}
		return (double) (sum / list.size());
	}

	// 獲取標準差
	public double getStandardDevition() {

		double sum = 0;
		for (int i = 0; i < list.size(); i++) {
			sum += ((double) list.get(i) - getAverage())
					* (list.get(i) - getAverage());
		}
		return Math.sqrt(sum / (list.size() - 1));
	}

	public static void main(String[] args) {
		GetAverageandStandardDevition gcs = new GetAverageandStandardDevition();
		System.out.println(gcs.getAverage());
		System.out.println(gcs.getStandardDevition());

		// upbase:3451726.682809466,downbase:2965000.3698221124
		// 上基线
		System.out
				.println(gcs.getAverage() + 1.960 * gcs.getStandardDevition());
		// 下极限
		System.out
				.println(gcs.getAverage() - 1.960 * gcs.getStandardDevition());
	}
}