Consider the sequence of coin tosses described in Exercise 1. (a) What is the expected number of tosses that will be required in order; to obtain five heads? (b) What is the variance of the number of tosses that will be required in order to obtain five heads?
Exercise 1
Suppose that a sequence of independent tosses are made with a coin lor which the probability of obtaining a head on any given toss is 1/30.
(a) What is the expected number of tails that will be obtained before five heads have been obtained?
(b) What is the variance of the number of tails that will be obtained before five heads have been obtained?