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?

Answer 1

Have you seen this kind of question before? If so, what did you do to arrive at the mean or expected value?

Hint: You have 3 possible outcomes, and you have the probability of each of them.
Create the following products:

0*0.2
1*0.5
2*0.3

Now what? I'm purposely not explaining what to do next in the hope that you can find info on "expected value of discrete variables" that will enable you to complete the solution of this problem.