#!/usr/bin/perl
use warnings;
use List::Util qw(sum);

my @list_of_numbers = (1 .. 50);
my $i = ();
my $a = ();

sub mean {
    return sum(@_)/@_;
}

sub above_mean {
    $i == mean(@list_of_numbers);
    foreach (@list_of_numbers) {
        if ($a > $i) {
            print "$a is above mean, which is mean(@list_of_numbers)";
        }
    }
}

print above_mean(@list_of_numbers);

##</code><code>##

Use of uninitialized value $a in numeric gt (>) at main.pl line 16.