Another possible manner to represent the possible results of an experiment is Venn Diagram. A Venn Diagram corresponds to a rectangle, a square, or a circle that contains bullets representing all possible results of an experiment. The next Figure illustrates a Venn and Tree Diagram for the Experiment of throwing a dice in which the head (H) face event has the probability p of happening and probability 1-p of happening tail (T) face.

Tree diagram for experiments with multiple stages 

Probability trees are useful for calculating combined probabilities for sequences of events. It helps you to map out the probabilities of many possibilities graphically, without the use of complicated probability formulas. The next figure shows the possible results from an experiment with dice thrown twice with a Tree diagram and its corresponding Veen Diagram.