Chapter 4
Probability and Counting Rules
Section 4-2
Sample Spaces and
Probability
Chapter 4
Probability and Counting Rules
Section 4-2
Exercise #13
Section 4-2 Exercise
#13
If two dice are rolled one time, find the probability of
getting these results.
a.
b.
c.
d.
e.
A sum of 6
Doubles
A sum of 7 or 11
A sum greater than 9
A sum less than or equal to 4
a. A sum of 6
b. Doubles
c. A sum of 7 or 11
d. A sum of greater than 9
e. A sum less than or equal to 4
Section 4-2 Exercise #17
In a college class of 250 graduating seniors, 50 have jobs
waiting, 10 are going to medical school, 20 are going to law
school, and 80 are going to various other kinds of graduate
schools. Select one graduate at random.
a. What is the probability that the student is
going to graduate school?
b. What is the probability that the student
is going to medical school?
c. What is the probability that the
student will have to start paying
back his deferred student loans
after 6 months (i.e. does not
continue in school)?
a. What is the probability that the student
is going to graduate school?
b. What is the probability that the student
is going to medical school?
c. What is the probability that the student will have to start
paying back his deferred student loans after 6 months (i.e.
does not continue in school)?
Section 4-2 Exercise
#27
A CBS News / New York Times poll found that of 764
adults surveyed nationwide, 34% felt that we are spending
too much on space exploration, 19% felt that we are
spending too little, 35% felt that we are
spending the right amount, and the rest
said “don’t know” or had no answer. If
one of the respondents is selected at
random, what is the probability that the
person felt that we are spending the
right amount or too little?
Chapter 4
Probability and Counting Rules
Section 4-3
The Addition Rules for Probability
Section 4-3 Exercise #17
Three cable channels (6, 8, and 10) have quiz shows,
comedies and dramas. The number of each is shown
here.
Type of
show
Quiz show
Comedy
Drama
Channel Channel Channel
6
8
10
5
3
4
2
2
4
1
8
2
If a show is selected at random, find these probabilities
a. The show is a quiz show, or it is shown on channel 8.
b. The show is a drama or comedy.
c. The show is shown on channel 10, or it is a drama.
a. The show is a quiz show, or it is shown on channel 8.
Type of Channel
show
6
Quiz show
5
Comedy
3
Drama
4
Total
Channel
8
2
2
4
Channel
10
1
8
2
Total
b. The show is a drama or comedy.
c. The show is shown on channel 10, or it is a drama.
Section 4-3 Exercise #19
The frequency distribution shown here illustrates the
number of medical tests conducted on 30 randomly
selected emergency patients.
Number of
Tests
Performed
0
1
2
3
4 or more
Number
of
Patients
12
8
2
3
5
The frequency distribution shown here illustrates the
number of medical tests conducted on 30 randomly
selected emergency patients. If a patient is selected at
random, find these probabilities.
a. The patient has had exactly 2 tests done.
b. The patient has had at least 2 tests done.
c. The patient has had at most 3 tests done.
d. The patient has had 3 or fewer tests done.
e. The patient has had 1 or 2
tests done.
a. The patient has had exactly 2 tests done.
b. The patient has had at least 2 tests done.
c. The patient has had at most 3 tests done.
d. The patient has had 3 or fewer tests done.
e. The patient has had 1 or 2 tests done.
Section 4-3 Exercise #23
If one card is drawn from an ordinary deck of cards,
find the probability of getting the following:
a. A king or a queen or a jack.
b. A club or a heart or a spade.
c. A king or a queen or a diamond.
d. An ace or a diamond or a heart.
e. A 9 or a 10 or a spade or a club.
If one card is drawn from an ordinary deck of cards,
find the probability of getting the following:
a. A king or a queen or a jack.
b. A club or a heart or a spade.
c. A king or a queen or a diamond.
d. An ace or a diamond or a heart.
e. A 9 or a 10 or a spade or a club.