1. Section 1.1: Equally Likely Outcomes
Outcome Space ()
The set of all possible outcomes of some situation or experiment.
Example: Tossing a fair coin.
 = {H,T}
Event
Something that might or might not happen, depending on the outcome of the situation or experiment. H T
H or T
Coin defies gravity and never lands.

2. Section 1.1: Equally Likely Outcomes
Probability
A measure of the likelihood or chance that an event occurs, given on a scale from 0 to 1.
A function of events, denoted by P.
e.g., P(H) or P(T).
Equally Likely Outcomes
Each member of the outcome space has the same chance (i.e., probability) of occurring.
Synonymous phrases: “picked at random”, “same chance”, “honest”, “fair”, “unbiased”
Example: Tossing a fair coin.
P(H) = 0.5
P(T) = 0.5

3. Section 1.1: Equally Likely Outcomes
Probability Computation for Equally Likely Outcomes
Let A be an event associated with an outcome space .
#() = total number of outcomes.
#(A) = number of outcomes in A.