You forgot to tell us the email of your teacher. Please update your post and add it.

When you've got a new question, please don't just overwrite the old one with it, because it will render all old answers worthless.

The people who gave the answers don't like that, and aren't inclined to help you with future problems then.

Just start a new Seekers of Perl Wisdom for each unrelated question.

The rest of this site might be useful to you as well.

Here's a hint: HASH

If you show me what you've got so far, I might be able to offer a better hint...

...roboticus

#!/usr/bin/perl
$_=<DATA>;
$h{$_}++,$c++,$h{$_}>$n?($n=$h{$_},$m=$_):++$k for map {lc}m/\w+/g;
$_="$c words\nmax: '$m' ($n times)$\avg count:".($c/keys %h).$\;
print;BEGIN{$\=$/;$/=q//; $,=":"}
print@a while@a=each%h;

__DATA__
But, in a larger sense, we can not dedicate—we can not consecrate—-we 
+can not hallow—-this ground. The brave men, living and dead, who stru
+ggled here, have consecrated it, far above our poor power to add or d
+etract. The world will little note, nor long remember what we say her
+e, but it can never forget what they did here. It is for us the livin
+g, rather, to be dedicated here to the unfinished work which they who
+ fought here have thus far so nobly advanced. It is rather for us to 
+be here dedicated to the great task remaining before us — that from t
+hese honored dead we take increased devotion to that cause for which 
+they gave the last full measure of devotion — that we here highly res
+olve that these dead shall not have died in vain — that this nation, 
+under God, shall have a new birth of freedom — and that government of
+ the people, by the people, for the people, shall not perish from the
+ earth
[download]

Update: now with average.

Here is the code (encrypted so other students can't steal it ;) ) Now if you can just decrypt it you'll be all set.