Coin tossing Problem 4:

3. Otherwise, one of the three coins lands differently from the other two... 

The definition of k is a little confusing. Maybe something like: "Let the 
random variable k be the order in the sequence that the odd coin occured."

Problem 5:

"fromt he set {1,2,..., pn!}" The sequence isn't positively clear that it is: 
1,2,3,4,...,pn!, maybe put in a couple more numbers?

Problem 7:

Um, oh crap, we have a Random Walk problem... Have we have any printed 
reference for students to work off of? I think in the review session we 
weren't clear if this was fair game. Can we send students a heads up that 
Random Walks are indeed fair game for the exam? 

I'm not sure how to phrase this heads up, maybe something like "Random Walks 
are fair game on the exam. We wouldn't expect you to be able to solve a new 
problem on your own, but we may ask you to reason about some problem you saw 
in lecture".