Different ways to express a proportion

The proportion of times that an event occurs is often expressed as a percentage (rate per hundred). It can equivalently be expressed as a rates per x values (where x is a number different from 100) or as a 'return period'. If the event has return period y, it has a rate of once per y values. For annual climatic events, it is called a y-year event.

The exercise below asks you to express a proportion in different ways.

Repeat with several different questions. (Make sure that you try at least one that asks for a percentage, one asking for a rate and one that requires a return period.)