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1.
A student is randomly selected from a large college. Define the events C = {the student owns a
cell phone} and I = {the student owns an iPod}. Which of the following is the correct
interpretation of the probability P(IC)?
A.
The chance that a randomly selected student
owns an iPod.
B.
The proportion of students who own a cell
phone who also own an iPod.
C.
The relative frequency of iPod owners who own
a cell phone.
D.
The percentage of students who own both a cell
phone and an iPod.
This is a conditional probability statement (notice the  symbol).
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
2.
For the following statement, determine if it is true or false. If two events A and B are mutually
exclusive, they must also be independent.
A.
True
B.
False
False; Just the opposite: if mutually exclusive then independent. Think of the events being Male
and being Female. These two events are mutually exclusive since you can only be in one of the
events. However, knowing that you are in event Male automatically disqualifies you from being
in event Female so the P(male) is dependent on P(female) and viceversa
Points Earned:
1/1
Correct Answer:
B
Your Response:
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3.
Suppose two different states each pick a twodigit lottery number between 00 and 99 (for a 100
possible numbers). What is the probability that both states pick the number 13?
A.
1/100
B.
1/200
C.
2/100
D.
1/10,000
Probability for each state is 1/100 and these are independent. So getting 13 for each state is
(1/100) times (1/100) = 1/10000
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
4.
From our Class Survey, 52% of the students reported having tried marijuana, and 24% of
students reported that they had tried marijuana and still smoke marijuana. What is the probability
that a student still smokes marijuana given that the student has tried marijuana?
A.
0.125
B.
0.76
C.
0.46
This is a conditional probability question, meaning you need to find P(Still gets high  Tried
Marijuana) = P(Still and Tried)/P(Tried) = 0.24/0.52 = 0.46 or 46%.
Points Earned:
0/1
Correct Answer:
C
Your Response:
A
5.
Which of the following is the sample space when 2 coins are tossed? [H = Head, T = Tail]
A.
{H, T, H, T}
B.
{HH, HT, TH, TT}
C.
{H, T}
The answer is {HH, HT, TH, TT}. When two coins are tossed, for either coin the outcome is a
Head or a Tail. Thus there are 2
2
= 4 possible outcomes.
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
6.
Correcly identify if the following random variables as either discrete or continous. The amount
of liquid in a gallon of orange juice.
A.
Discrete
B.
Continuous
Keep in mind that a gallon is a measurement and that if you buy a gallon of OJ you probably do
not get
exactly
one gallon.
Points Earned:
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This note was uploaded on 12/06/2009 for the course STAT 200 at Pennsylvania State University, University Park.
 '08
 BARROSO,JOAOR
 Statistics, Probability

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