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.

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

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.