4. a. A batch of 50 parts contains six defects. If two parts are drawn randomly one at a time without replacement, what is the probability that both parts are defective? b. If this experiment is...

4. a. A batch of 50 parts contains six defects. If two parts are drawn randomly one at a time
without replacement, what is the probability that both parts are defective?
b. If this experiment is repeated, with replacement, what is the probability that both parts
are defective?