number of users logged in script

Shell Programming and Scripting
1

My admin needs a shell script in Korn that will show conditions based on users logged in. I have never used the Korn shell and have no clue what I am doing, can anyone help.

here are the conditions that need to be returned.

if users are below 5
displays should be: performance is high

if users are below 10
displays should be: performance is average

if users are above 15
displays should be: system is slow

Im sure this is to be in some kind of loop or case statement. Well i think so any way!!!

2 
num=$(who | wc -l)
if [ $num -lt 5 ]
then
   echo performance is high
elif [ $num -lt 10 ]
then
   echo performance is average
elif [ $num -lt 15 ]
then
   echo performance is slow
fi