One in four adults is currently on a diet. You randomly select eight adults and ask them if they are currently on a diet. Find the probability that the number who say they are currently on a diet is (a) exactly three, (b) at least three, and (c) more than three

a) 0.2076

b) 0.3216

c) 0.114  

Explanation:

We are given the following information:

We treat adult on a diet as a success.

P(Adult on diet) = = 0.25

Then the number of adults follows a binomial distribution, where

where n is the total number of observations, x is the number of success, p is the probability of success.

Now, we are given n = 8

We have to evaluate:

(a) exactly three

(b) at least three

(c) more than three