Question

Suppose that 20% of the time Henry eats out twice a week, 25% of the time he eats out once a week, and 55% of the time he doesn't eat out at all in a given week. What is the expected value for the number of times Henry eats out during a week?

Answer 1

ANSWER :

The expected value is 0.65 which is less than once in a week.

EXPLANATION :

Henry eats out during a week :

20% of the time, he eats out twice a week

25% of the time, he eats out once a week

and

55% of the time, he doesn't eat out at all in a week.

Get the sum of the product of the percentage with the number of times he eats in a week.

20%(2) + 25%(1) + 55%(0)

That will be :

$0.2(2)+0.25(1)+0.55(0)=0.65$