Question

a chimp is taking a multiple choice test. Of course the chimp can’t read and is guessing for every question. If there are 4 choices for each question, and there are 84 questions on the test, how many questions can we expect the chimp to answer correctly? (hint: There is a 25% chance that the chimp will guess correctly .)

Answer 1

1/4×84=21

21 questions

I think!

Answer 2

We can expect the chimp to answer 21 questions correctly.

Explanation:

There are 4 choices for each question, and there are 84 questions on the test.

There is a 25% chance that the chimp will guess correctly.

This question is a binomial Problem where n = 84 and p = 0.25

We have to find the mean here.

Mean = np =
`84(0.25)` = 21

Hence, we can expect the chimp to answer 21 questions correctly.