Venn Diagrams (Cambridge (CIE) A Level Maths): Revision Note

Venn Diagrams

What is a Venn diagram?

• A Venn diagram is a way to illustrate events and are particularly useful when outcomes overlap

• Venn diagrams are mostly used for 2 or 3 events

• A Venn diagram consists of a box (rectangle) and a bubble (circle/ellipse) for each event

  • Bubbles may or may not overlap

  • Bubble(s) is not a technical term, but we like it!

• The box represents all outcomes

  • It is often referred to as the Universal Set and is commonly labelled with the symbols  (Kunstler script font uppercase letter E)  (Greek lowercase letter Xi)

  • There is no standardised symbol for this purpose

• Bubbles are labelled with their event name (A, B, etc)

• The numbers inside a Venn diagram (there should be one in each region) will represent either a frequency or a probability

  • In the case of probabilities being shown, all values should total 1

What do the different regions and bubbles overlapping mean on a Venn diagram?

• This will depend on how many events there are and how the outcomes overlap

• Venn diagrams show ‘AND’ and ‘OR’ statements easily