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What is Probability?. Probability is the likelihood of something happening.Probability is expressed as a fraction as the number of desired outcomes over the number of possible outcomes.. Probability. The highest probability of an event occurring is:1The lowest probability of an event occurring is:0.
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1. by Trip Lenahan
2007-2008
2. What is Probability?
Probability is the likelihood of something happening.
Probability is expressed as a fraction as the number of desired outcomes over the number of possible outcomes.
3. Probability The highest probability of an event occurring is:
1
The lowest probability of an event occurring is:
0
4. Professions That Use Probability Insurance companies
Professional card players
Casino operators
Athletes
Sports Analysts
Statistics keepers
Secretaries
Accountants
Doctors
5. Two-Step Procedure To determine probability, one may use this two-step procedure:
1. Determine and count all logical possibilities
2. Determine and count all desired possibilities or “winners”
6. Probability Formula
The Probability Formulas are as follows:
p= number of winners
total number of possibilities
OR
p= winning region
total possible region
7. Example of Probability #1
If there are 10 balls (7 red, 3 green) then the likelihood of selecting a red ball on one attempt is ….
7 red balls (winners)
10 total balls (total possibilities)
8. Example of Probability #2 Problem: If one of the four points is picked randomly, what is the probability that the point lies on CA?
9. Example of Probability #2 (cont) To solve this problem, we first list all
possibilities
A B C D
Then, we circle the winners
A B C D
10. Example of Probability #2 Solution Therefore the probability of the selected point being on the angle is:
Winners = 3
Possibilities 4
11. Practice Problem #1 If one of the four angles is selected randomly, what is the probability that the angle is acute?
12. Example of Probability #3 Problem: If two of the four points are picked at random, what is the probability that both lie on CA?
13. Example of Probability #3 AB BC CD
AC BD
AD
14. More Probability (pg 52 #10) If point B is chosen on AC, what is the probability that -5 < B < 7?
15. Still more… (pg 52 #11) The second hand of a clock sweeps continuously around the face of the clock. What is the probability that at any random moment the second hand is between 7 and 12?
16. Last one… (pg 52 #15) If a point is chosen at random in rectangle ABCD, what is the probability that:
a. It is in square SQUA?
17. Last one (really)… (pg 52 #15) If a point is chosen at random in rectangle ABCD, what is the probability that:
b. It is not in square SQUA?