The mailing list of an agency that markets scuba-diving trips to the Florida Keys contains 70% males and 30% females. The agency calls 30 people chosen at random from its list.
What is the probability that the first woman is reached on the fourth call? (That is, the first 4 calls give MMMF.)
P(x=k) = (n choose k)p^k(1-p)^(n-k)
The Attempt at a Solution
since they want MMMF does it make sense to do just go
.7 * .7 * .7 * .3 and then divide by 4C1 =4