Multiple Choice Identify the
choice that best completes the statement or answers the question.


1.

An assignment of probability must obey which of the
following?
a.  The probability of any event must be a number between 0
and 1, inclusive.  b.  The sum of all the
probabilities of all outcomes in the sample space must be exactly 1.  c.  The probability of an event is the sum of the outcomes in the sample space
which make up the event.  d.  All of the
above.  e.  A and B only. 


2.

Students at University X must be in one of the
class ranks—freshman, sophomore, junior, or senior. At University X, 35% of the students are
freshmen and 30% are sophomores. If a student is selected at random, the probability that her or she
is either a junior or a senior is



In a particular game, a fair die is tossed. If the
number of spots showing is either four or five, you win $1. If the number of spots showing is six,
you win $4. And if the number of spots showing is one, two, or three, you win nothing. You are going
to play the game twice.


3.

The probability that you win $4 both times
is
a.  1/6  b.  1/3  c.  1/36  d.  1/4  e.  1/12 


4.

The probability that you win money at least once in
the two games is
a.  .75  b.  .50  c.  .25  d.  .125  e.  .1 



An event A will occur with probability 0.5.
An event B will occur with probability 0.6. The probability that both A and B
will occur is 0.1.


5.

The conditional probability of A given
B is
a.  0.5.  b.  0.3.  c.  0.2.  d.  1/6.  e.  cannot be
determined from the information given. 


6.

Experience has shown that a certain lie detector
will show a positive reading (indicates a lie) 10% of the time when a person is telling the truth and
95% of the time when a person is lying. Suppose that a random sample of 5 suspects is subjected to a
lie detector test regarding a recent oneperson crime. Then the probability of observing no positive
reading if all suspects plead innocent and are telling the truth is
a.  0.409  b.  0.735  c.  0.00001  d.  0.590  e.  0.99999 


7.

If you buy one ticket in the Provincial Lottery,
then the probability that you will win a prize is 0.11. If you buy one ticket each month for five
months, what is the probability that you will win at least one prize?
a.  0.55  b.  0.50  c.  0.44  d.  0.45  e.  0.56 


8.

Suppose that A and B are two independent events
with P(A) = .2 and P(B) = .4. P(A Ç
B^{c}) is
a.  0.08.  b.  0.12.  c.  0.52.  d.  0.60. 


9.

A plumbing contractor puts in bids in on two large
jobs. Let the event that the contractor wins the first contract be A and the event that the
contractor wins the second contract be B. Which of the Venn diagrams has shaded the event that the
contractor wins exactly one of the contracts?


10.

A die is loaded so that the number 6 comes up three
times as often as any other number. What, then, is the probability of rolling a
6?
a.  .125  b.  .250  c.  .375  d.  .500  e.  None of the
above. 
