sample questions from a test on discrete probability distributions

1. MultipleChoice Problem Solving
One in three adults is currently on a diet. The
following is a binomial probability distribution of a
random selection of 8 adults, and x is the number
of adults on a diet.
What is the probability that at least 4 of the adults
are on a diet?
a. .17 b. .92
c. .25 d. .33
x 0 1 2 3 4 5 6 7 8
p(x) 0.04 0.16 0.28 0.27 0.17 0.07 0.02 0.00 0.00

2. Fillinblank(s) Binomial Distribution Graphs
Given a graph:
Estimate the mean and standard deviation of the
binomial distribution. μ = ______ σ = ______
-0.02
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

3. MultipleChoice
Discrete Probability Distributions
Which of the following is NOT a discrete probability
distribution?
a. b.
c. d.
x p(x)
0 0.24
1 0.40
2 0.26
3 0.09
4 0.01
5 0.00
x p(x)
0 0.03
1 0.16
2 0.31
3 0.31
4 0.16
5 0.03
x p(x)
0 0.59
1 0.33
2 0.07
3 0.01
4 0.00
5 0.00
x p(x)
0 0.20
1 0.35
2 0.20
3 0.01
4 0.00
5 0.00

4. MultipleSelection Binomial Experiments
Which one of the following does NOT describe a
binomial experiment?
 In any bag of M&M candies 1 out of every five
candies is blue. What is the probability that from
a randomly selected sample of 20 candies, 8 of
them are blue?
 A bag of M&M candies has 12 red, 15 brown, 5
blue, 7 yellow and 9 green candies. If a candy is
randomly selected from the bag, what is the
probability the candy is blue?

5. MultipleSelection Classify Random Variables
Determine which of the following random variables
are not discrete.
the number of car at the intersection of Park and
Reservoir avenue
oThe amount of water in an 18’ x 30’ in ground
pool
o The number of digital artifacts in a student’s
graduation portfolio
oThe amount of time a student uses to make a
graduation portfolio presentation
oThe number of college applications a student
makes

6. True/False Binomial Experiments
A binomial experiment consists of a fixed number
of trials and a probability of success that is
constant.

7. True/False Probability Distributions
If P(x) is a probability distribution, then the sum of
the p(x) lies inclusively between 0 and 1.

8. Fillinblank(s)
Expected Value
In New Jersey’s Pick 4 lottery game, you pay $.50 to
select a sequence of digits such as 1332. If you select the
same sequence of 4 digits that are drawn, you win and
collect $2788. The following table shows the probability of
winning, the probability of losing, and the net gain or loss
associated with each event.
The expected value of New Jersey’s Pick 4 lottery game is
$__________________.
Probability of
winning
0.0001 Net Gain $2,787.50
Probability of
losing
0.9999 Net Loss -$0.50

9. MultipleSelection Discrete Probabiliy Distributions
The expected value and standard deviation of the popular lottery
game, PowerBall are approximately $.50 and $15,000 respectively.
Which of the following statements are true?
 If you play the Powerball regularly, you can expect to win at
least $.50.
 If you play the Powerball regularly, you can expect to gain a
lot or lose a lot of money.
 If you play the Powerball regularly, it is highly unlikely that you
will win more than $15,000.
 If you play the Powerball regularly, you can expect to win
$.50 cents most of the time.
 If you play the Powerball regularly, you the average of your
wins and losses is $.50.