What term describes the average number of years that persons at a given age are expected to live?

The term that describes the average number of years that persons at a given age are expected to live is known as life expectancy. This concept is crucial in demographics and health statistics, as it offers insights into the longevity of populations and influences various fields, including insurance and public health policy.

Life expectancy is calculated using mortality rates and provides an estimate based on current age and gender. For example, if the life expectancy for a person at the age of 65 is 20 years, this means that, on average, individuals who reach that age can expect to live for another 20 years. This metric is essential in understanding the longevity of life and helps inform financial planning, retirement benefits, and healthcare services.

The other terms mentioned, such as "law of large numbers," relate to statistical principles but do not specifically define the average lifespan. "Life income option" and "life annuity" are financial products related to retirement income, but they do not describe the concept of expected years of life based on age. Thus, life expectancy is the most accurate term for this concept.