/* _______________________________________________________________ */


void local_statistics (void)

/* Calculates the mean and standard deviation for mm data points */
/* in the array data[256]    , where mm < 256                    */ 
/* uses several global variables for I/O, mm, mean,stddev,data[] */ 
{
int i,n;
float sum,sum2;
sum=0.0;
sum2=0.0;
n=mm;

	for (i=0;i<n;i++)
		{
		sum = sum+(float) data[i];
		sum2 = sum2 + (float) (data[i]*data[i]);
		}

mean=sum/((float) n);
stddev=sqrt((sum2/(float) (n-1))-(sum*sum)/((float)n*(float)(n-1)));


}

/* _______________________________________________________________ */