java代码实现方差,方差的代码

java求方差

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相关问答

Q1: 在Java中怎么求方差和标准差

Java求方差和标准差：

public class GetAverageandStandardDevition {

private int[] array = new int[10];

private int num = 10;

public int getRandomDigit() {

return (int) (Math.random() * 1000);

}

public void getTargetDigit() {

for (int i = 0; i num; i++) {

array[i] = getRandomDigit();

System.out.println(array[i]);

}

}

//方差

public double getAverage(){

int sum = 0;

for(int i = 0;i num;i++){

sum += array[i];

}

return (double)(sum / num);

}

//标准差

public double getStandardDevition(){

double sum = 0;

for(int i = 0;i num;i++){

sum += Math.sqrt(((double)array[i] -getAverage()) * (array[i] -getAverage()));

}

return (sum / (num - 1));

}

public static void main(String[] args) {

GetAverageandStandardDevition gcs = new GetAverageandStandardDevition();

gcs.getTargetDigit();

System.out.println(gcs.getAverage() + " " + gcs.getStandardDevition());

}

Q2: java中怎样编写计算方差的程序

import java.util.Scanner;

public class NumTest {

public static void main(String[] args){

double num=0;

Scanner s = new Scanner(System.in);

System.out.println("请输入你需要计算的个数：");

int n = s.nextInt();

double[] list=new double[n];

for (int i = 1; i = n; i++) {

System.out.println("请输入第"+i+"个数:");

list[i-1]=s.nextDouble();

num+=list[i-1];

}

double mean=num/n;

double var=0;

for(double d:list){

var+=(d-mean)*(d-mean);

}

System.out.println("方差是:"+var/n);

}

}