#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#define N 100
main(){
int a[N],n,i;
float aver,s;
float sum=0,e=0;
printf("input:");
scanf("%d",&n);
printf("input %d 个样本",n);
for(i=0;i<n;i++){
scanf("%d",&a[i]);
sum+=a[i];
}
aver=sum/n;
for(i=0;i<n; i++)
e+=(a[i]-aver)*(a[i]-aver);
e/=n-1;
s=sqrt(e);
printf("The mean is %.2f and the variance is %. 2f, standard deviation is %.2f",aver,e,s);
}