Question

A coin is unbalanced such that it comes up tails 55% of the time.

a.what is the probability that you don't flip a head until the fourth flip?
b.what is the probability that you don't flip a tail until the fourth flip?
c.how many tosses would it take, on average, to flip a head?
d.how many tosses would it take, on average, to flip a tail?

Answer 1

a. P[TTTTH] = .55^4*.45 = .0412

b. P[HHHT] = .45^4*.55 = .0226

c. 1/.45 = 2.222

d. 1/.55 = 1.818