Discrete Probability and Expected Values

The random variable X, representing the number of nuts in a chocolate bar has the following probability distribution. What is the mean?

• 1.3

• 1.5

• 1.7

• 1.9

If two coins are tossed once, which is NOT a possible value of the random variable for the number of heads?

• 0

• 1

• 2

• 3

Which of the following is a discrete random variable?

• Length of electrical wires

• Number of pencils in a box

• Amount of sugar used in a cup of coffee

• Voltage of car batteries

It is a numerical quantity that is assigned to the outcome of an experiment.

• Random Variable

• Variable

• Probability

• Probability Distribution

How many ways can a "double" come out when you roll two dice?

• 2

• 4

• 6

• 8

It is the central or average of its corresponding probability mass function.

• Mean

• Variance

• Standard Deviation

• Probability

What is the mean outcome if a pair of die is rolled once?

• 1.5

• 2.5

• 3.5

• 4.5

Find the mean of the probability distribution involving the random variable X that gives the number of heads that appear after tossing four coins once.

• 4

• 3

• 2

• 1

The probabilities that a printer produces 0,1,2, and 3 misprints are 42%, 28%, 18%, and 12% respectively. What is the mean value of the random variable?

• 1

• 2

• 3

• 4

A random variable X has a mean of 12 and a standard deviation of 3.2. What is the corresponding z-score for x = 8?

• -1.25

• -1.50

• -1.75

• -2.25