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)"
+;
         }
#........^ this is missing
    }
#...^ so is this
}
[download]

#!/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);
[download]

This now returns:

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

However, I thought I declared $a earlier in my program?

== is the numeric comparison operator, not the assignment operator, which is quite similar: =. See perlop for details. warnings should have told you:

Useless use of numeric eq (==) in void context at ...
[download]

Also, you don't populate $a anywhere. Maybe, you meant

foreach my $a (@list_of_numbers) {
[download]

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

print above_mean(@list_of_numbers);


Just as a matter of curiosity, you might try this variation on the quoted statement:
    print above_mean();
Does calling the  above_mean() function without any parameters make any difference to the value returned by the function? If not, why not?

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Give a man a fish:  <%-(-(-(-<

++ for tagging it as homework, providing code, errors, etc.

You have been given some advice already, let me add my $0.02.

• @_ contains the parameters to a sub. See (original) lines 11 for use, and line 14/15 for lack of use.
• Declare variables as close to use as possible (usually). Line 16 => foreach my $a (@list_of_numbers) {. See also your use of $i on line 15. Declare it right there.
• Your requirements state that you want to return the list of numbers. Are you sure you want to print on line 18? Perhaps grep would help. As an example, to return a set of numbers that are between 4 and 8, you could do something like grep { $_ > 4 && $_ < 8 } @numbers. This could probably be used to replace you entire foreach loop. Conversely, look at push to store the results within your foreach loop.
• Line 15 does not do what you think it does. You are using ==, a comparison operator, when you want =, an assignment operator.
• Instead of the call on line 18 to mean(@list_of_numbers) (which does not do what you think it does within the string), why not just use $i, which you have already calculated.
• I would probably choose different variable names. $a => $number, $i => $mean, @list_of_numbers => @numbers. The '@' sigil indicates an array, so 'list_of_' is redundant. $i needs me to look back to its assignment to remember what it actually holds. $a is not as far, but it has the same problem. Anything that can be done to keep the person from having to backtrack when reading your code makes it easier to read.
• Kudos on using List::Util for calculating the sum. Easy enough to do by hand, but since that isn't the purpose of the exercise, there is no sense cluttering up the assignment with support code.

#!/usr/bin/perl
use strict;
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);
[download]

Thanks for the suggestion, I could use that (big time). It still doesn't execute with the correct bracket location, however. Looking into it now... I'm a complete beginner with programming, and Perl. This community has been nothing but helpful to me. Thanks again!

"Correct bracket location" doesn't enter into it.

The hint is that your final print statement is deeply indented after tidying. It is indented to the same level as the if statement, because that's where it goes based on the brackets you wrote.

You didn't want it to be at the same level as the if statement, and that's the clue that you need to add the close brackets.

This might help

#!/usr/bin/perl -w

sub above_mean
{
    my @array=@_;
    my $sum=0;
    foreach $i (@array)
    {
        $sum+= $i;
    }
    
    my $mean = $sum/ @array;
    
    return grep { $_ > $mean} @array;
}

my @a=1..100;
foreach my $i (above_mean(@a))
{
    print "$i\n";
}
[download]

And how does this help the OP?

In case you hadn't noticed, this is a homework question. Giving the OP a working solution (that they likely won't understand) isn't the aim here - helping the OP develop their own working solution (whilst learning the skills required to do so) is the entire point of the exercise.

Thank you for your concern, however, I was able to come up with my own solution before this was posted. In any means, this post was another example of how I could reach my end goal, but i was able to forge my own path to get there. Thanks again!

foreach $i (@array) { ... }


Posted code won't run under strictures due to non-declaration of  $i iterator. Making  $i lexical fixes this:
    foreach my $i (@array) { ... }
(Running with  use strict; and  use warnings; is highly recommended for beginning Perl programmers — and for non-beginners as well!)

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Give a man a fish:  <%-(-(-(-<