計算標準差

Python：

import numpy as np
arr = [1,2,3,4,5,6]
#求均值
arr_mean = np.mean(arr)
#求方差
arr_var = np.var(arr)
#求標準差
arr_std = np.std(arr,ddof=1)
print("平均值爲：%f" % arr_mean)
print("方差爲：%f" % arr_var)
print("標準差爲:%f" % arr_std)

Java:

public class Demo {
	
	public static void main(String[] args) {
		int[] array = {15,96,85,88,18,58,68,16,6,99,88,11,8,36,82,44,55,66};
		int sum = 0;      
		for(int i=0;i<array.length;i++){
		    sum += array[i];      //求出數組的總和
		}
		System.out.println(sum);  //939
		double average = sum/array.length;  //求出數組的平均數
		System.out.println(average);   //52.0
		int total=0;
		for(int i=0;i<array.length;i++){
		    total += (array[i]-average)*(array[i]-average);   //求出方差，如果要計算方差的話這一步就可以了
		}
		double standardDeviation = Math.sqrt(total/array.length);   //求出標準差
		System.out.println(standardDeviation);    //32.55764119219941
	}
	
}