# 5.1 Expected Value

5 Questions | Total Attempts: 105  Settings  • 1.
What is the expected value of the random variable representing the number observed on a single roll of a six-sided die?
• 2.
A customer randomly selects three RAM modules from a shipment of seven known to contain two defective modules. What is the probability that the customer chooses exactly one defective module? Leave your answer as a fraction in lowest terms.
• 3.
A tetrahedron has four equal triangular faces. The faces of a tetrahedral die are labelled with the numbers one, three, five, and seven. What is the expected value of the random variable representing the number observed on a single roll of this die?
• A.

3

• B.

3.5

• C.

4

• D.

5

• 4.
When we compare the possible values for a discrete random variable to its expected value, the following statement must be true.
• A.

The possible values and the expected value must all be whole numbers.

• B.

The expected value must be one of the possible values.

• C.

The possible values must all be whole numbers but the expected value may be a rational number.

• D.

The expected value will not be a whole number.

• 5.
The following table is a valid probability distribution for a random variable X. What must be the value for P(2) to complete the table? X P(X) 0 0.1 1 0.3 2   3 0.2