Concept

Theoretical Probability

When all outcomes in a sample space are equally likely to occur, the theoretical probability of an event is the ratio of the number of favorable outcomes to the number of possible outcomes.

P(event)=Number of favorable outcomes/Number of possible outcomes

Consider the roll of a standard six-sided die. There are six equally likely outcomes in the sample space. For the event of rolling an even number, there are three favorable outcomes. This can be called A.

A sample space of rolling a dice: {1,2,3,4,5,6}; the event A of rolling an even number consists of three outcomes {2,4,6}.

The probability of A can be found by using the given ratio. P(A) = Number of favorable outcomes/Number of possible outcomes = 3/6 After simplification, it is obtained that P(A) is equal to 12. Consequently, there is a 50 % chance an even number is rolled.

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