Question: 1. A device has probability p of operating successfully on any trial in a sequence. What probability p is necessary to ensure the probability of successes on all of the first four trials is 0:85? With that value of p, what is the probability of four or more successes in five trials?
2. A survey form is sent to 100 persons. If they decide independently whether or not to reply, and each has probability 1/4 of replying, what is the probability of k or more replies, where k = 15; 20; 25; 30; 35; 40?