Algebra 2 Honors
Conditional Probability
Joel surveyed his classmates and asked “Do you like school?” The results are as follows:
Find the probability of randomly selecting a classmate who
1)
2)
3)
4)
5)
6)
7)
8)
likes school
is not a female
likes school, given they are female
is a male, given they do not like school
is a female, given they like school
has no opinion, given they are female
does not like school, given they are female
likes school, given they are male
The question, "Do you smoke?" was asked of 100 people. Results are shown in the table.
Use the table to answer #1 – 5.
.
Male
Female
Total
Yes
19
12
31
No
41
28
69
Total
60
40
100
What is the probability of a randomly selected individual is
9)
a male?
14)
P(Yes | male )
10)
a male and smokes?
15)
P( male | yes)
11)
a female, given that the individual smokes?
16)
P(no | female)
12)
a smoker, given that they are female?
17)
P( female | no )
13)
not a smoker, given that they are male?
18)
P(female and smokes)
19.
Andrea is a very good student. The probability that she studies and
passes her mathematics test is 17 . If the probability that Andrea
20
studies is 15 , find the probability that Andrea passes her
16
mathematics test, given that she has studied.
20.
The probability that Janice smokes is 3
Smokes and develops lung cancer is 4
. The probability that she
10
. Find the probability that
15
Janice develops lung cancer, given that she smokes.
21.
The probability that Sue will go to Mexico in the winter and to France
in the summer is 0.40 . The probability that she will go to Mexico in
the winter is 0.60 . Find the probability that she will go to France this
summer, given that she just returned from her winter vacation in
Mexico.
22.
A die is tossed. Find P(less than 5 | even) .
23.
A number is selected randomly from a container containing all the
integers from 10 to 50 . Find:
a) P(even | greater than 40)
b) P( greater than 40 | even)
c) P( prime | between 20 and 40)
Answers
1.
.667
2.
.576
3.
.714
4.
.625
5.
.455
6.
.0714
7.
.214
8.
.632
9.
.6
10.
.19
11.
.387
12.
.3
13.
.683
14.
.317
15.
.613
16.
.7
17.
.406
18.
.12
19.
68
75
20.
8
9
21.
2
3
22.
2
3
23. a)
1
2
b)
5
21
c)
4
19