Question

Nina goes to the supermarket 0, 1, or 2 times in a week. The probability that she goes 0 days is 0.2, the probability that she goes 1 day is 0.50, and the probability that she goes 2 days is 0.30. What is the expected value of the number of days per week on which Nina goes to the supermarket? 0.8

Answer 1

1.1

Explanation:

I got it right on the Edmentum Test

Answer 2

The probability that Nins goes 0 days is 0.2, the probability that she goes 1 day is 0.50, and the probability that she goes 2 days is 0.30. You can write these data as a table:

`image`

where
`x_i` are numbers of days and
`p_i` are probabilities.

The expected value of the number of days per week on which Nina goes to the supermarket is

`E(X)=\sum\limits_(i=1)^3x_ip_i=0\cdot 0.2+1\cdot 0.5+2\cdot 0.3=0.5+0.6=1.1`.

Answer: the expected value of the number of days per week on which Nina goes to the supermarket is 1.1.