计算变异系数的 C++ 程序


我们给定了一个大小为 n 的浮点数组,任务是找出变异系数并显示结果。

什么是变异系数?

在统计测量中,变异系数用于通过给定的数据找出变异范围。在金融方面,变异系数用于找出投资额涉及的风险金额。如果标准差与均值之间的比率较低,则投资所涉及的风险也较低。变异系数是标准差与均值之间的比率,由以下公式得出:

变异系数 = 标准差 / 均值 

示例

Input-: array[] = { 10.0, 21, 23, 90.0, 10.5, 32.56, 24, 45, 70.0 }
Output-: coefficient of variation is : 0.75772

Input-: array[] = { 15.0, 36.0, 53.67, 25.45, 67.8, 56, 78.09}
Output-: coefficient of variation is : 0.48177

给定程序中使用的解决方法如下:

  • 输入包含浮点值的数组
  • 计算给定数组上的均值和标准差
  • 通过用标准差除以均值来计算变异系数值
  • 将结果作为变异系数显示 

算法

Start
Step 1-> declare function to calculate the value of mean
   float cal_mean(float arr[], int size)
   Declare float sum = 0
   Loop For i = 0 and i < size and i++
      Set sum = sum + arr[i]
   End
   return sum / size
Step 2-> declare function to calculate the value of standard deviation
   float StandardDeviation(float arr[], int size)
   Declare float sum = 0
   Loop For i = 0 and i < size and i++
      Set sum = sum + (arr[i] - cal_mean(arr, size)) * (arr[i] -
   End
   Call cal_mean(arr, size))
   return sqrt(sum / (size - 1))
Step 3-> Declare function to calculate coefficient of variation
   float CoefficientOfVariation(float arr[], int size)
   return StandardDeviation(arr, size) / cal_mean(arr, size)
Step 4-> In main()
   Declare an array of float arr[] = { 10.0, 21, 23, 90.0, 10.5, 32.56, 24, 45, 70.0}
   Calculate the size of array as int size = sizeof(arr) / sizeof(arr[0])
   Call function as CoefficientOfVariation(arr, size)
Stop

示例

 实际操作

#include <bits/stdc++.h>
using namespace std;
// function to calculate the mean.
float cal_mean(float arr[], int size) {
   float sum = 0;
   for (int i = 0; i < size; i++)
   sum = sum + arr[i];
   return sum / size;
}
//function to calculate the standard deviation
float StandardDeviation(float arr[], int size) {
   float sum = 0;
   for (int i = 0; i < size; i++)
   sum = sum + (arr[i] - cal_mean(arr, size)) * (arr[i] - cal_mean(arr, size));
   return sqrt(sum / (size - 1));
}
// function to calculate the coefficient of variation.
float CoefficientOfVariation(float arr[], int size) {
   return StandardDeviation(arr, size) / cal_mean(arr, size);
}
int main() {
   float arr[] = { 10.0, 21, 23, 90.0, 10.5, 32.56, 24, 45, 70.0};
   int size = sizeof(arr) / sizeof(arr[0]);
   cout<<"coefficient of variation is : "<<CoefficientOfVariation(arr, size);
   return 0;
}

输出

coefficient of variation is : 0.75772

更新时间:2019-12-23

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