Ten jelly beans are selected, one at a time from a bowl containing 10 black, 10 red and 10 green jelly beans ...

  

1. Ten jelly beans are selected, one at a time from a bowl containing 10 black, 10 red and 10 green jelly beans. Let x represent the number of green jelly beans selected in 10 draws from the bowl.
(A)  If this experiment is completed without replacing the jelly beans, explain why x is not a binomial random variable.
(B)  If this experiment is completed with replacement of the jelly beans, explain why x is a binomial random variable.

2. In testing a new drug, researchers found that 10% of all patients using it will have a mild side effect. A random sample of 13 patients using the drug is selected. Find the probability that:
 
(A) exactly two will have this mild side effect
(B) at least three will have this mild side effect.