#!/usr/bin/awk -f
# this awk program calculates the average of the numbers found in the lines of the input file

BEGIN {
        num_samples = 0;
        sum = 0;
        sqrsum = 0;
}
{
        val = $0;
        sum += val;
        sqrsum += val*val;
        num_samples++;
}
END {
        print "num_samples = " num_samples;
        print "sum = " sum;
        print "sqrsum = " sqrsum;
        print "average = " sum/num_samples;
        devsqr = (sqrsum - sum*sum/num_samples)/(num_samples-1);
        if (devsqr<=0)
          print "devsqr <= 0";
        else
          print "std. deviation = " sqrt(devsqr);
}