ABSTRACT
Most human activities carry some degree of risk. Many risks are known to a relatively high degree of accuracy, because data have been collected on their historical occurrence. For example, the number of deaths caused by motor vehicle accidents in 1 year is divided by the total number of people at risk (e.g., the entire US population) for an actual individual risk of 1/4500 from dying of such an accident. Based on a 70-year lifetime, people in the US have a 1/65 probability of dying in a car accident over an entire lifetime.
