Venn diagrams are used to sort sets of data. The probability of an event not happening uses the complement of the region on the Venn diagram. Count the number of elements in each region. Redraw ...

Use Venn diagrams to illustrate data in a logical way which will enable you to see groupings and sets clearly.

Venn had initially used diagrams developed by the Swiss mathematician Leonard Euler to show some relationships between sets, which he then developed into his famous Venn diagrams.