Probablity

Probablity

1. Outcome: Possible results of experiment.

2. Sample space: set of all possible outcomes

3. Event: subset of sample space

4. Experiment: Any observation measurement of random phenomenon.

5. Odds: Compares # of favorable outcomes to # of unfavorable outcomes

6. Formulas

   • Theorical probability
     • P(E)= # of favorable outcomes / Total outcomes
   • Empirical Probability
     • P(E)= # of times an event occurred / total outcomes

7. Events Involving "not" or "or"

   • Probability of complement
     • P(not E)=1-P(E)
   • Addition Rule of probability
     • If A and B are any two events:
       • P(A or B) = P(A) + P(B) - P(A an B)
     • If they are mutually exclusive
       • P (A or B) = P(A)+P(B)
         • Enter text here
   • Impossible event: P=0
   • Probability value: 0<P(E)<1
   • Certain event: P(E)=1

8. Events involving "and"

   • Multiplication rule of probability
     • For any two events: P(A and B) = P(A) - P(B)
     • For independent events: P(A and B) = P(A) * P(B)
   • Conditional Probability formula
     • P (A n B) / P (A)
       • Probability of event B assuming event A happened, conditional probability of B given A

9. Venn diagrams

   • Union
     • A u B
   • Difference
     • A - B
   • Intersection
     • A n B
   • Complement
     • A´