Probability Review

Probability is a measure of how likely an event is to occur, expressed as a number between 0 (impossible) and 1 (certain).

A probability of 0 means that the event cannot happen.

A probability of 1 means that the event is certain to happen.

The probability of getting heads is 1/2.

The probability of rolling a 3 is 1/6.

An event is a specific outcome or a set of outcomes of a random experiment.

The sample space is the set of all possible outcomes of a random experiment.

The probability of picking a red ball is 4/10 or 2/5.

A complementary event is the event that represents all outcomes not included in the event of interest.

The probability that it will not rain is 1 - 0.3 = 0.7.