求数组的方差

float get_variance(float*a,int n){float mean,sum1=0;int i;for(i=0;i<=n-1;i++) { sum1+=a[i]; } mean=sum1/n;float variance,sum2=0;for (i=0;i<=n-1;i++) { sum2+=(a[i]-mean)*(a[i]-mean); } variance=sum2/n;return variance;}