Basic Rules of Probability
Objectives
• Determine if events are mutually
exclusive.
• Use probability rules to determine
the probability of an event.
• Use a Venn diagram to determine
probability of an event.
Vocabulary
• mutually exclusive - events that cannot
occur at the same time
Determine if the following
events mutually exclusive.
• E is the event of “being a doctor”
and F is the event of “being a
women”
• E is the event of “being single” and F
is the event of “being married”
• E is the event of “being a plumber”
and F is the event of “being a stamp
collector”
Probability Rules
p ()  0
p (S )  1
0  p (E )  1
Probability Rules
p (E )  p (E ')  1
p (E  F )  p (E )  p (F )  p (E  F )
p (E  F )  0
if E and F are mutually exclusive
Standard Deck of Cards
Find the probability of each of
the following:
• a jack and a heart
• a jack or a heart
• not a jack of hearts
• above a jack
• below a three
Find the probability of each of
the following:
• both above a jack and below a three
• either above a jack or below a three
• not a jack of hearts
• above a five
• below a jack
If o(E) = 1:6, then find o(E’ ).
Rolling a Pair of Dice
Find the probability that the sum
when a pair of dice is rolled is
• 8 or 10
• even and less than 5
• even or less than 5
Alex is taking two courses, algebra
and U. S. history. Student records
indicate that the probability of
passing algebra is .35, that of failing
U. S. history is .35, and that of
passing at least one of the two
courses is .80. Find the probability
that
• Alex will pass history
• Alex will pass both courses
Alex is taking two courses, algebra
and U. S. history. Student records
indicate that the probability of
passing algebra is .35, that of failing
U. S. history is .35, and that of
passing at least one of the two
courses is .80. Find the probability
that
• Alex will fail both courses
• Alex will pass exactly one course