Definition 2.1. 1. The outcomes in a sample space S are equally likely if each outcome has the same probability of occurring. In general, if outcomes in a sample space S are equally likely, then computing the probability of a single outcome or an event is very straightforward, as the following exercise demonstrates.

How do you know if outcomes are equally likely?

If outcomes are equally likely, then the probability of an event occurring is the number in the event divided by the number in the sample space. The probability of rolling a six on a single roll of a die is 1/6 because there is only 1 way to roll a six out of 6 ways it could be rolled.

When all possible outcomes are equally likely?

Equally likely means that each outcome of an experiment occurs with equal probability. For example, if you toss a fair, six-sided die, each face (1,2,3,4,5,or6 1 , 2 , 3 , 4 , 5 , or 6 ) is as likely to occur as any other face. If you toss a fair coin, a Head (H ) and a Tail (T ) are equally likely to occur.