A drawer contains r red socks, b blue socks and w white socks' Assume you randomly pull a sock from

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A drawer contains r red socks, b blue socks and w
white socks. Assume you randomly pull a sock
from the drawer. 1. What is the probability
that the sock is red?2. What is the probability
that the sock is NOT white?3. What is the
probability that the sock is green?
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• PROBABILITY
• Probability Theory is the study of chance
• Experiment a situation with several possible
  results
• Outcomes results

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Experiment Outcome Toss a coin heads/tails
Toss a coin twice
HH, HT, TH, TT
Roll a die
1,2,3,4,5,6
Roll a die twice and take the sum
2,3,4,5,6,7,8, 9,10,11,12
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• Sample Space is the set of all possible outcomes
  of the experiment
• Must look at and examine the experiment carefully
• Infinite sample space
• Finite sample space

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• Scratch Paper
• Two different dice are rolled and the numbers
  that appear are recorded
• Write out the sample space

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• Event any subset of the sample space
• EXAMPLE
• For the experiment tossing two dice, list the
  outcomes in the event doubles, that is getting
  the same number on both die.

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• Probability of an event is between 0 and 1
• Can be written in any form, as a decimal,
  fraction or a percent
• Write the probability of 1 in 4 in all three
  forms

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• Probability of an event
• P(E) number of outcomes
• number of outcomes in the sample space
• All outcomes must be equally likely this is
  called fair or unbiased

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• EXAMPLE
• Flip two fair coins
• Find the probability of getting heads once
• P(one head)
• P(two heads)
• P(zero heads)

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• EXAMPLE 3
• Two fair dice are rolled
• Find P(sum of dice 7)
• Find P(sum of dice 1)
• Find P(sum of dice lt10)
• Find P(sum of dice lt50)

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• EXAMPLE 4
• A family has three children
• List the sample space
• Find P(one boy)

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HOMEWORK

• Read pg425 and read section 7-1
• Page4311-9,13-15