posted by Mike on .
The local video store has determined that 65% of the store's customers are women. What is the probability that the next 3 customers will be women? Round to the nearest percent.
p = .65
(1-p) = .35
binomial distribution, n = 3
binomial coefs for n = 3 are 1, 3, 3, 1
probability of three women, zero men in three = coef(3,0)(p)^3 (1-p)^0
= 1 (.65)^3 (1)
= .2746 = 27%
Of course I made this too hard. Since it is the trivial case of all the same, not for example two men and one woman, you could just say 3 independent events each with a probability of .65 or .65^3