An experiment when repeated under identical condition does not produce the same result every time but outcome is one of the several possible outcomes, then such an experiment is known as a random experiment. For example, before rolling a die we do not know the result, but after the experiment, the result of the random experiment is known.

An outcome is a result of a random experiment, this is also known as an event. The set of all possible outcomes is called the  sample space.

Tossing a coin, sample space: \(S = \{ H,\;T\} \)

Tossing 2 coins, sample space: \(S = \{ HH,\;TH,HT,\,TT\} \)

Tossing a coin and rolling a dice, sample space: \(S = \{ H1,\;H2,\;H3,\;H4,\;H5,\;H6,\;T1,\,T2,\,T3,\,T4,\,T5,\,T6\} \)

Example 01: Three dice are rolled together, how many elements are there in the sample space?