C ++程序实现分组数据的标准差
在本教程中，我们将讨论实现分组数据标准差的程序。
为此，我们将给出班级间隔和班级频率。我们的任务是找到分组数据的标准偏差。
示例
#include <bits/stdc++.h>
using namespace std;
//查找分组数据的均值
float calc_mean(float mid[], int freq[], int n){
float sum = 0, freqSum = 0;
for (int i = 0; i < n; i++) {
sum = sum + mid[i] * freq[i];
freqSum = freqSum + freq[i];
}
return sum / freqSum;
}
//查找数据的标准偏差
float calc_deviation(float lower_limit[], float upper_limit[], int freq[], int n){
float mid[n], sum = 0, freqSum = 0, sd;
for (int i = 0; i < n; i++) {
mid[i] = (lower_limit[i] + upper_limit[i]) / 2;
sum = sum + freq[i] * mid[i] * mid[i];
freqSum = freqSum + freq[i];
}
sd = sqrt((sum - freqSum * calc_mean(mid, freq, n) * calc_mean(mid, freq, n)) / (freqSum - 1));
return sd;
}
int main(){
float lower_limit[] = { 50, 61, 71, 86, 96 };
float upper_limit[] = { 60, 70, 85, 95, 100 };
int freq[] = { 9, 7, 9, 12, 8 };
int n = sizeof(lower_limit) / sizeof(lower_limit[0]);
cout << calc_deviation(lower_limit, upper_limit, freq, n) << endl;
return 0;
}输出结果
15.757