Todennäköisyyspiiri

Todennäköisyyspiiri (literally “probability circle”) is a pedagogical visualization used in Finnish statistics education to illustrate basic probability ideas. In its common form, the diagram is a circle representing the sample space, divided into regions or sectors. Each sector corresponds to an event or outcome, and the sector’s size is proportional to the event’s probability, so that the sum of all sectors equals one. The circle format aims to give students a concrete sense of relative likelihoods and how probabilities add up.

Different classroom versions adapt the circle to show more advanced ideas. Some versions highlight conditional probability by shading a portion of a sector to indicate the probability of an event given another event, while others use multiple concentric layers or color coding to demonstrate joint distributions or mutually exclusive events. Because there is no single formal definition, the exact construction varies between curricula and authors.

Todennäköisyyspiiri is primarily a teaching aid rather than a formal mathematical object. It is often discussed alongside other visualization tools such as pie charts and Venn diagrams, and it appears in Finnish textbooks and online resources aimed at introductory probability and statistics.