1. 6.4 probability January 06, 2012
Warm Up
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8
1 6
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Objective: finding probability and odds
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2. 6.4 probability January 06, 2012
Outcomes possible results of an action. There are six
outcomes for rolling a single number cube: 1, 2, 3, 4, 5, 6.
An event is any outcome or group of outcomes. The outcomes are called favorable
outcomes. In rolling two number cubes, for example, rolling a sum of 4 is an event
corresponding to three favorable outcomes shown here.
Probability of an event = P(event) = number of favorable outcomes
number of possible outcomes
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3. 6.4 probability January 06, 2012
Find P(even number) with one number cube.
All probabilities range from 0 to 1.
0 0.5 1
Impossible event Certain Event
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4. 6.4 probability January 06, 2012
Complement is the opposite of an event.
In the United States, the probability that a child is a twin is 2 in 90, or 2 . Find P(not a twin).
90
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5. 6.4 probability January 06, 2012
Probability ratio of part
whole
Odds ratio of part
part
number of favorable outcomes
odds in favor = number of unfavorable outcomes
odds against = number of unfavorable outcomes
number of favorable outcomes
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6. 6.4 probability January 06, 2012
You draw a name at random from a hat holding the names of 6 girls and 8 boys.
What are the odds in favor of choosing a boy?
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7. 6.4 probability January 06, 2012
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