Select Code to Download

sub std_dev {
  my ($sum, $sqr_sum);
...
  }
  sqrt(($sqr_sum - $sum * $sum / @_)/@_);
}

# Produces an unbiased estimate of a standard deviation
# from a sample
...
  }
  sqrt(($sqr_sum - $sum * $sum / @_)/$#_);
}