平均、分散、標準偏差の求め方

calculate.c

#include<stdio.h>
#include<math.h>

double Average(double *data,int n);
double Verb(double *data,int n);
double Deviation(double *data,int n);

	//平均を計算
	double Average(double *data,int n)
	{
		int i;
		double average=0;

		for(i=0;i<n;i++)
		{
			average += data[i];
		}			
		return (average/n);
	}
	
	//分散を計算
	double Verb(double *data,int n)
	{
		int i;
		double average=0;
		double verb=0;
		average = Average(data,n);

		for(i=0;i<n;i++)
		{
			verb += data[i]*data[i];
		}			
			verb /=n;
			verb -= average*average;
			
		return verb;
	}
	//標準偏差を計算
	double Deviation(double *data,int n)
	{
		return(Verb(data,n));
	}
	
	int main(void)
	{
	double data[3]={1.0,1.0,1.0};//テスト用の配列
	const int n = sizeof data /sizeof data[0];//配列の要素数
	printf("標本数:%d\n",n);
	printf("平均:%f\n",Average(data,n));
	printf("分散:%f\n",Verb(data,n));
	printf("標準偏差:%f\n",Deviation(data,n));
	return 0;
	}

calculate.php

<?php
/*
*実行結果は:http://ideone.com/bltVV
*/

//平均の算出
function Average($array){
$result=0;
	foreach($array as $value)
	{
		$result += $value;
	}
	
	$result =($result/count($array));	
	return $result;
}

//分散の算出
function Verb($array)
{
	$result=0;
	$E_x = Average($array);
		foreach($array as $value)
		{
			$result += $value*$value;
		}
	
		//V(X)=E(X^2)-E(X)^2	より、分散を算出
		$result /= count($array);	//E(X^2)を算出
		$result -= $E_x * $E_x;//E(X)^2を引く
	
		return $result;
}

function Deviation($array)
{
	return sqrt(Verb($array));

}

//テスト用の入力値
$array_1= Array(1,1,1,1,1);
$array_2= Array(1,2,3);

//結果1
printf("平均:%f,分散:%f,標準偏差:%f",Average($array_1),Verb($array_1),Deviation($array_1));
?>