probability

 Probability: is the branch of mathematics which deals with study of phenomena or randomized experiments.
 Experiment: it is a process that leads to occurrence of one of several possible obsevations, in the process a result or observation is produce, in this process one or more values are obtains.
 Sample space: it is also called probability space. Are all possible outcome of a experiment is the set of the obtained values.
 Event or happening: it is each one of the possible outcomes of a randomized experiment.