Short Quiz 1 (Probability Distribution)

The sum of the probabilities in a probability distribution is always equal to what value?

• 100

• 1

• 1%

• None of the choices.

Which of the following probabilities serves as the values of a probability distribution?

• P(1) = 0.08, P(2) = 0.12, P(3) = 1.03

• P(1) = 10/33, P(2) = 1/3, P(3) = 12/33

• P(1) = 0.42, P(2) = 0.31, P(3) = 0.37

• P(1) = 0, P(2) = 0.71, P(3) = 0.39

Which of the following probabilities serves as the values of a probability distribution?

• P(1) = 1/19, P(2) = 10/19, P(3) = 5/19, P(4) = 5/19

• P(1) = 0.25, P(2) = 0.75, P(3) = - 0.25

• P(1) = 0.15, P(2) = 0.27, P(3) = 0.29, P(4) = 0.29

• P(1) = 1/4, P(2) = - 1/8, P(3) = 1/2, P(4) = 3/8

The probabilities that a customer will buy 1, 2, 3, 4, or 5 items in a grocery store are 3/10, 1/10, 1/10, 2/10, and 3/10, respectively. What is the average number of items that a customer will buy?

• 1.3

• 2.11

• 3.1

• 3.4

In what interval should be the value of a probability take place?

• 0 $\le$ P(X) $\le$ 1

• - 1 < P(X) $\le$ 1

• Both given intervals.

• None of the choices.

If P(X) = X/6, what are the possible values of X for it to be a probability distribution?

• 0, 2, 3

• 1, 2, 3

• 2, 3, 4

• 1, 1, 2

If P(X) = $\frac{x-2}{5}$ , what are the possible values of X for it to be a probability distribution?

• 2, 3, 3, 4, 5 

• 1, 2, 3, 4, 5

• 2, 3, 4, 5, 6

• 2, 2, 3, 4, 5

The probabilities that a surgeon operates on 3, 4, 5, 6, or 7 patients in a day are 0.15, 0.10, 0.20, 0.25, and 0.30, respectively. Find the average and variance number of patients that a surgeon operates on a day.

• 5.45 & 1.9475

• 4.54 & 1.9475

• 5.45 & 1.7954

• 4.54 & 1.7954

Which of the following is a discrete random variable?

• The average amount of electricity consumed.

• The number of needles used in an acupuncture patient.

• The amount of paint used in repainting a house.

• The average weight of female athletes.

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

• 1

• 2

• 3

• 0