Section 1 Probability and Odds
Dec 30, 2015
Section 1Probability and Odds
Vocabulary
probability: how likely it is an event will occur
experiment: taking a measurement or making an observation
experimental probability: probability determined by observation or measurement
outcome: result of each trial of an experiment
Experimental Probability
number of favorable observations of ( )total number of observations
EP E
• Probability is between 0 and 1.
• If probability is 0 then it is IMPOSSIBLE for the event to occur
• If probability equals 1 then the event is CERTAIN to occur
Ex 1
• Find the probability of rolling a number greater than two on a die
Ex 2• A class contains 6 students with black
hair, 8 with brown hair, 4 with blonde hair, and 2 with red hair. Find P(black)
• Find P(red or brown)
• Find P(not blonde)
Ex 3Lions fans
attending a recent 3-game series were asked whether the team should have a mascot. The table shows the results of the survey.
What is the probability that a Lions’ fan wants a mascot?
GameGame AttendancAttendancee
In favor In favor of of
mascotmascot
Friday 681 388Saturday 527 428Sunday 928 786
Ex 4A softball player has had 24
hits in her first 60 times at bat. Predict her number of hits in 330 at bats.
theoretical probability: the ratio of favorable outcomes to the number of possible outcomes in a sample space
number of favorable outcomes( )number of possible outcomes
P T
Experimental probability approaches theoretical probability as more trials are performed in an experiment.
Ex 5A card is picked at random from a standard
deck of 52 cards. Find P(face card).
Find P(#7)
Standard Card Deck• 52 cards total• 2 colors (red, black)• 4 suits (hearts, diamonds, spades, clubs)• 13 cards per suit (A,2,3,4,5,6,7,8,9,10,J,Q,K)• 3 face cards per suit (J, Q, K)
odds: the ratio of favorable outcomes to the number of unfavorable outcomes
number of favorable outcomes( )number of unfavorable outcomes
O T
Ex 5What are the
odds of rolling a 4 on a standard number cube?
Ex 6What are the odds of rolling a 4 on a
standard number cube?
Find the odds of rolling a number greater than two.
What are the odds of rolling not a 2 or 3?
Ex 7
• A card is selected at random from a standard deck of 52 cards. What are the odds against selecting a 2 or a 3?