Question

A barrel of 20 apples has 2 rotten apples and 18 good apples. 7 apples are selected at random from the barrel. What is the expected number of good apples selected

Answer 1

Answer:

Expected value = 7 x 0.9 = 6.3

Step-by-step explanation:

Probability of getting a good apple is 18/20 = 0.9

Probability of getting a bad apple is 2/20 = 0.1

This follows a binomial distribution because either you get a good apple or a bad apple.

The expected value of a binomial distribution is given as n*p where n is number of trials and p is the probability of success.

In this case our number of trials is 7 and the probability of success is 0.9, since the trials are for getting good apples.

Hence

n = 7

p = 0.9

Expected value = 7 x 0.9 = 6.3