Probability 1.1-1.4

Probability 1.1-1.4

1. Concepts

   • EXPERIMENT: Any observation measurement of a random phenomenon.
   • EVENT: Subset of a sample space
   • SAMPLE SPACE: The set of all possible outcomes
   • OUTCOME: Possible results of the experiment
   • ODDS: Compares the number of favorable outcomes to the number of unfavorable outcomes.

2. Formulas

   • THEORICAL PROBABILITY: P(E) = Number of favorable outcomes / Total outcomes
   • EMPIRICAL PROBABILITY: P(E) = Number of times an event occurred / Total outcomes

3. Venn Diagrams

   • Union (A u B)
     • Union of A and B
   • Difference (A - B)
     • B without A
   • Intersection (A n B)
     • Part of intersection of A and B
   • Compemet (A´)
     • Everything except A

4. Events with "not" or "or"

   • Impossible event
     • P = o, can´t happen
   • Certain Event: P(E) = 1
   • Probability Value
     • 0<P(E)<1
   • Probability of complement
     • P (not E) = 1- P(E)
   • Addition rule of probability
     • Any two events
       • P(A or B) = P(A) + P(B) - P(A and B)
     • Mutually exclusive
       • P(A or B) = P(A) + P(B)
         • Mutually exclusive can´t happen together

5. Events with "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 that event A already happened. It is called Conditional probability of B given A