Download Compound Event - Brookwood High School

Section 6.4
Find Probabilities of
Compound Events
Compound Event: A compound event
combines two or more events, using the word
"AND" or the word "OR".
Mutually Exclusive Events: Events with no
common outcomes
Overlapping Events: Events with at least one
common outcome
Independent Events: The occurrence of one
event has no effect on the occurrence of the
other
Dependent events: The occurrence of one
event affects the occurrence of the other
Conditional probability: If A and B are
dependent events, then the probability that
event B will occur given that event A has
occurred is called the conditional probability
of B given A.
Example 1
Find the probability of A OR B
You randomly choose a card from a
standard deck of 52 playing cards.
a. Find the probability that you choose a 9 or a King.
Are these events overlapping or mutually exclusive?
P(9 or King) = P(9) + P(King)
b. Find the probability that you choose an Ace or a
spade. Are these events overlapping or mutually
exclusive?
P(Ace or spade) = P(Ace) + P(spade) - P(Ace and spade)
Example 2
Find the probability of A AND B
You roll two number cubes (dice). What is
the probability that you roll a 1 first and a 2
second? Are these events dependent or
independent?
P(1 and 2) = P(1) x P(2)
Example 3
Find the probability of A and B
A box contains 8 red markers and 3 blue
markers. You choose one marker at random,
do not replace it, then choose a second
marker at random. What is the probability
that both markers are blue? Are these
events dependent or independent?