An advertisement for Cold-Ex claims an 80 percent end-of-treatment clinical success rate for the treatment of flu. Twelve flu patients are given Cold-Ex and are later checked to see if the treatment was successful. Let's assume that the claim is correct. Find the probability that: 1. Exactly 8 have been cured
2. At least 10 have been cured
3. Fewer than 5 have been cured
4. Between 6 and 9 (including 6 and 9) have been cured.