2.4 Introduction to Probability

Calculate probabilities for events and their complements.

• The sample space of a random process is the set of all possible nonoverlapping outcomes. The probability of the sample space is 1.
• If all outcomes in the sample space are equally likely, then the theoretical probability an event E will occur is Enumber of outcomes in event total number of outcomes in the sample space . The probability of event E occurring is written as P ()E .
• The probability of an event is a number between 0 and 1, inclusive.
• The probability of the complement of an event E, which can be written as E′, E, or EC (i.e., the probability of “not E”) is equal to 1- PE() .