Probability.doc

Probability
The likelihood of the occurrence of an event. The probability of event A is written P(A). Probabilities are always numbers between 0 and 1, inclusive.
The four basic rules of probability:
1. For any event A, 0 ≤ P(A) ≤ 1.
2. P(impossible event) = 0.
Also written P(empty set) = 0 or P() = 0.
3. P(sure event) = 1.
Also written P(S) = 1, where S is the sample space.
4. P(not A) = 1 – P(A).
Also written P(complement of A) = 1 – P(A)   or   P(AC) = 1 – P(A)   or   .
If all outcomes of an experiment are equally likely, then

Sigma Notation
Continued Sum
A notation using the Greek letter sigma (Σ) that allows a long sum to be written compactly.