Warm-Up

On a spinner below, each numbered section is
exactly 1/8 of the spinner. Find the probability
of each event in three spins of the spinner.

Exactly one number is 8 or greater than 3
REMEMBER….

Quiz Friday over 10.3-10.6

Ch. 10 Test: March 18
10.6
Dependent Events and
Probability
Words to know….
A Conditional Probability occurs when some
condition is known that may affect the probability
of an event.
Conditional Probability:
The conditional probability of event B, given
event A, denoted by ,
P( A and B) where
P( A)  0.
P( B | A) 

P( A)
Example 1:

The band at Villesdale High School has 50
members, and the student council has 20
members. Five student council members are
also in the band. Suppose that a student is
randomly selected form these two groups

Find the probability that the student is a member
of the band if you know that he or she is on the
student council.
You Try:

The Wilmont High School honor society has
20 member, and the school’s debate teach has
18 members. Twelve members of the debate
teach are also in the honor society. Suppose
that a student is randomly selected from these
two groups.

Find the probability that the student is a member
of the debate team if it is known that he or she is
a member of the honor society.
Example 2:

Using the table below find:
 P(paper | recycled)
 P(recycled | paper)
Material
Recycled
Total
26.5
Not
Recycled
44.5
Paper
Other
18.5
110.5
129
Total
45
155
200
71
Example 3:



A bag contains 5 blue and 8 yellow marbles.
For each case below find the probability of
randomly selecting a blue marble on the first
draw and a yellow marble on the second draw.
The first marble is replaced.
The first marble is not replaced.
Example 4:

For one roll of a number cube, let A be the
event “even” and let B be the event “2”. Find
each probability.



P(A)
P(A and B)
P(B|A)
Practicing will help you remember…

P. 668 #9-29odd

Finish the 10.6 worksheet

Quiz FRIDAY over 10.3-10.6!!!