Prepared by Dr. Agatha Shaw, Valencia College, 9/19/2007
http://faculty.valencia.cc.fl.us/ashaw
QUICK REVIEW: CLAST SKILL II.D.3
Identify the probability of a specific outcome
Some Guidelines:
* Complement Rule:
)
(
1
)
(
C
A
P
A
P
=
* General Addition Rule: For any two events, the probability of A or B
is
)
(
)
(
)
(
)
(
B
A
P
B
P
A
P
B
A
P
+
=
[
0
)
(
=
B
A
P
when A and B are disjoint events.]
* General Multiplication Rule: For any two events, the probability of A and B is
)
|
(
)
(
)
(
A
B
P
A
P
B
A
P
=
[
)
(
)
|
(
B
P
A
B
P
=
when A and B are independent events.]
1. Suppose the probability of getting a 4.0 GPA at Valencia College is 4%. What is the
probability of NOT getting a 4.0 GPA?
a) 0.36 b) 0.96 c) 0.04 d) 0.16
2. A cookie jar contains five chocolate cookies, two peanut-butter cookies, and seven almond cookies.
If two cookies are grabbed from the jar at random without replacement. What is the probability
that neither cookies are almond cookies?
a) 14
7
14
7 b) 13
6
14
7 c) 13
8
14
7 d) 14
9
14
7
3. Suppose 50% of laser printers sold at Orange County are manufactured in the US, 30% in China,
10% in Mexico, 10% in other countries. What is the probability that laser printer selected at
random is made in China or Mexico?
a) 0.03 b) 0.35 c) 0.40 d) 0.60
4. If 50% of laptops auctioned at e-bay are made in Taiwan, 20% in Canada, 20% in the U.S. and 10%
in other countries. What is the probability that two laptops selected at random consecutively are
made in other countries?
a) 0.20 b) 0.10 c) 0.02 d) 0.01
5. Based on a survey done by a statistics class, the probability that a violin needs a monthly tuning is
0.30; the probability that it needs string(s) replacement is 0.60; and the probability that the violin
needs either a monthly tuning or string(s) replacement is 0.72. What is the probability that both a
monthly tuning and string(s) replacement are needed?
a) 0.90 b) 0.72 c) 0.18 d) 0.12
6. Suppose 44% of an apartment tenants lease a car, 55% of them subscribe to high-speed internet,
and 30% of them lease a car and subscribe to high-speed internet. If you randomly ask one of these
tenants, what is the probability that this person is either leasing a car or subscribing to high-speed
internet, or both?
a) 0.95 b) 0.30 c) 0.69 d) 0.19
