Which word is a noun meaning the rate at which events occur?

• A. Incidence
• B. Impromptu
• C. Inclination
• D. Implicate

Answer: (A)

You're being asked for a noun that names how often events occur. Incidence is the term used in statistics and public health to describe the number of new cases or events in a population over a defined period, effectively capturing the rate at which things happen. For example, you might hear about the incidence of a disease per 1,000 people per year, which directly conveys how frequently new cases arise. The other words don’t express this idea of frequency: impromptu describes spontaneity or something done without planning; inclination means a tendency or preference; implicate means to show involvement in something. So incidence is the precise noun for the rate of occurrence.