Statistics
posted by Carrie on .
A batch consists of 20 bad apples and 80 good ones. What is the probability of selecting 2 good apples when two are randomly selected if the first selection is replaced before the second is made?

With replacement, the probability of selecting a good apple stays at 60/80=3/4.
For a twostep experiment, the probability is the product of individual steps, hence, probability of select a good apple in each pick is
(3/4)^2=9/16