In life-table notation, p_x denotes what?

• A. The probability of surviving one year from age x
• B. The probability of dying within one year from age x
• C. The net premium at age x
• D. The mortality rate at age x

Answer: (A)

In life-table notation, p_x is the probability that a person aged x survives to age x+1—that is, they live one more year. It can be written as p_x = l_{x+1} / l_x, where l_x is the number alive at exact age x and l_{x+1} the number alive at exact age x+1. Since the two possible outcomes over a one-year interval are survival or death, the probability of dying within that year is q_x = 1 − p_x. Mortality rate or force (often denoted mu_x or related) and pricing quantities like the net premium are separate concepts and not what p_x represents.