Select Code to Download

sub standard_deviation {
  # declared all at once
  my ($mean, $std_dev) = (0,0);
...
  # and $size was removed, so we use @_ again
  return $std_dev / @_;
}

sub standard_deviation {
  my ($mean, $std_dev) = (0,0);

...
  $std_dev += ($_ - $mean)**2 for @_;
  return $std_dev / @_;
}