Name: _________________________________________________
Date: _________________________
CHS Statistics
Chapter 15 Practice
Conditional Probability and the Multiplication Rule
Period:______
In exercises 1-3, classify the events by indicating on the lines whether the events are independent
or dependent of each other.
1.
Finding that your kitchen light is not working. Finding that your
refrigerator is not working.
2.
Selecting a king from a standard deck, replacing it, and then selecting a
queen from the deck.
3.
Returning a rented movie after the due date and being charged a late
fee.
Find the probabilities for exercises 4- 11.
4. A box contains glass lenses used for traffic signals. Five of the lenses are red, four are yellow, and
three are green. If two of the lenses are randomly selected from the box, find the probability that
they are both yellow.
a. Assume that the first lens is replaced before the second lens is selected.
b. Assume that the first lens is not replaced before the second lens is selected.
5. Probability Experiment: Rolling a die and then picking a card
a. Rolling a 3 and picking an Ace
b. Rolling an even number and picking a black card
6. Probability Experiment: Picking a card from a deck, not replacing it, and then picking another
card
a. Picking a four, then picking another four
b. Picking a heart, then picking a diamond
c. Picking a queen, then picking a face card
7. Probability Experiment: Picking a card from a deck, replacing it, and then picking another card
a. Picking a four, then picking another four
b. Picking an ace, then picking a face card
8. A pool of potential jurors consists of 20 men and 25 women. If two different people are randomly
selected from this pool, find the probability that they are both women.
9. If you make random guesses for three multiple-choice test questions (each with five possible
answers), what is the probability of getting at least one correct?
10. Left-Handed People: In a sample of 1000 people. 120 are left-handed. Two unrelated people are
selected at random without replacement.
a. Find the probability that both people are left-handed.
b. Find the probability that neither person is left-handed.
11. If a couple plans to have 8 children, find the probability that they are all of the same gender.
12. In a shipment of 20 air conditioners, there are 4 with defective thermostats. If a random sample of
3 different air conditioners is selected, what is the probability that at least 1 will have a defective
thermostat?
13. In a survey of 320 students, the numbers studying various languages were found to be:
French = 160
Spanish = 100
Latin = 140
Spanish and French = 40
Spanish and Latin = 30
French and Latin = 70
All three Languages = 20
Let F = French, S = Spanish, L = Latin, ∩ = and, U = or
a.) P(F or S) =
d.) P(S ∩ L) =
b.) P(F|S) =
e.) P(F U S U L) =
c.) P(L | F) =
14. Refer to the chart below to answer the following questions:
Blood Type
O
A
B
AB
Positive
156
139
37
12
Negative
28
25
8
4
Total
184
164
45
16
Let P=Positive and N= Negative
a.) P(A ∩ P) =
c.) P(B U N) =
b.) P( P|O) =
d.) P(AB | N) =
Total
344
65
409