Answer:
a) The expected value is
b) The variance is
Step-by-step explanation:
We can assume that both marbles are withdrawn at the same time. We will define the probability as follows
#events of interest/total number of events.
We have 10 marbles in total. The number of different ways in which we can withdrawn 2 marbles out of 10 is .
Consider the case in which we choose two of the same color. That is, out of 5, we pick 2. The different ways of choosing 2 out of 5 is . Since we have 2 colors, we can either choose 2 of them blue or 2 of the red, so the total number of ways of choosing is just the double.
Consider the case in which we choose one of each color. Then, out of 5 we pick 1. So, the total number of ways in which we pick 1 of each color is . So, we define the following probabilities.
Probability of winning:
Probability of losing
Let X be the expected value of the amount you can win. Then,
E(X) = 1.10*probability of winning - 1 probability of losing =
Consider the expected value of the square of the amount you can win, Then
E(X^2) = (1.10^2)*probability of winning + probability of losing =
We will use the following formula
Thus
Var(X) =
