Ok that's better. There are still 2 issues with this code. The first is the condition:
"numHours" >= 8
currently you use "numHours" which is a string but what you really want to use here is the variable numHours that you declared as the parameter of the function here:
var sleepCheck = function(numHours)
So because running the function with a value of 10 by using
sleepCheck(10) will assign a value of 10 to numHours. You end up comparing a number to a number which makes sense, doesn't it?
Now the other problem is the location of your function call. Currently it is inside of the function at a position where it cannot be reached as both options (if and else) have a return statement inside of them you definitively leave the function before getting there. So just move this after the } of your function.