@Ing256 - yes, I know about maths thanks!
My point was that when you have a binary process (succeed in stun or not) and an discrete number of characters who can be affected (5 toons in a team) then this is very easily analysed as a binomial problem (as in fact are most things in this game).
But yes, if you calculate the expectation from the distribution i gave then you get E(toons stunned) = 2.999 = approx 3.
So I agree with you! Just trying to give a bit more detail to where the answer comes from and what we might actually expect to see happen - i.e. we would usually expect to see 2,3, or 4 toons stunned more than 80% of the time.