Probability
7.4
Classic Probability Problems
All Probabilities range from 0 to 1
Outcomes
• Possible results of an action
• Examples:
– 6 outcomes for rolling a dice (1,2,3,4,56)
– 2 outcomes for flipping a coin (heads or tails)
Favorable Outcome
• The outcomes that correspond to a specific
event.
• The outcome you are looking for.
Event
• The outcome or group of outcomes
Probability of an Event
favorable outcomes
P(event ) 
possible outcomes
Find the probability of rolling one
number cube
• P(odd number)
3 1
6 2
1
6
• P(2)
• P(5 or 6)
2
6
1
3
Consider the following:
There are 7 marbles in a bag. One is
green , 3 are blue, and 3 are yellow.
• Find the probability of choosing a yellow.
• P(yellow) = 3/7
• Find the probability of choosing a green.
• P(green) =1/7
Consider the possibilty of chosinfg one
card from a standard deck of playing
cards.
• What is the probablity of choosing a 7?
• What is the probabiltiy of choosing a black
card?
• What is the probability of choosing a red ace?
Using RODRIGUEZ find the probabiluyt
of choosing the letter …
• r
• P(r)= 2/9
• I
• P(I)=1/9
10 socks are placed in a laundry bag.
Use the following statements to
determine the number of socks of a
particular color.
•
•
•
•
Probability of blue is 0.30
Probability of black is 20%
Probability of argyle is 0.40
Probability of white is 0.10
Homework
• Workbook Page 107 (1-11) all