Ahem. One slight correction. Instead of the functional looking...

sub average {
    my $average;
    $average = sum(@_)/ scalar(@_);
    return($average);
}
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...which is really just a verbose way of saying...

sub average { sum(@_) / scalar(@_) }
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...I'm sure you meant the much easier to understand alternative...

sub average
{
    my @arr = @_;
    my $average = 0;
    my $length = @arr;

    for(my $x=0; $x<$#arr; $x++)
    {
        $average = $average + $arr[$x]/$length;
    }

    return $average;
}
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