0.11 Probability and Odds
Vocab-
Outcomes- the possible results
Favorable Outcome- The outcomes that you
want to occur.
Probability- a measure of the likelihood that
an event will occur.
Way to write probability...
P(event) = # favorable outcomes
# possible outcomes
P(5) = 1
6
=16.7%
P ( 1 or 5)
2 Types of Probability
Theoretical Probability-
Knowing all the likely outcomes
ex. rolling dice
Experimental ProbabilityResults based on trials of an
experiment.
Making Predictions from Probability
Find the experimental probabiltiy
Multiply by the number that will be attempted
Last year, Alexa planted 12 tulip bulbs, but only 10 of them
bloomed. This year, she intends to plant 60 tulip bulbs. How
many will bloom based on experimental probability?
ex. coin toss
50
OddsWhen all outcomes are equally
likely, the ratio of favorable to
unfavorable is called ODDS IN
FAVOR.
odds in favor =
favorable outcomes
unfavorable outcomes
Ratio of unfavorable to favorable is
ODDS AGAINST.
odds against = unfavorable outcomes
favorable outcomes
Suppose you randomly choose one letter
from A through J.
What are the odds in favor of choosing a
vowel?
3
7
What are the odds against choosing a
vowel?
7
3
Tree Diagram - a way to count the number of
possibilities.
When 1 event can occur in m ways and a 2nd
event can occur in n ways, multiply them
together!
A sandwich shop makes egg salad, tuna salad, and chicken salad
on wheat or white bread. Make a tree diagram to count the
number of possible sandwich choices.
EX. rolling 2 number cubes (dice)
Salad
egg
tuna
chicken
Bread
white
wheat
white
wheat
white
wheat
Die 1
6 different
sandwich
choices!
6 outcomes
Die 2
6 outcomes
There are 36 possible outcomes!
Finding probability
A museum is offering $20 off an art print to each 20th visitor.
You visit on Thursday and again on Friday. What is the
probability that you will receive the $20 off coupon on both
days?
1
400