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IAI Actuarial Core Principles · Risk Modelling and Survival Analysis · Concepts of survival models

A life aged 40 has future lifetime T_40 with constant force of mortality mu = 0.02 per year at all ages. What is the probability that this life dies between ages 45 and 50? Give the nearest value.

The probability is e^-0.1 minus e^-0.2, which is about 0.0861. With a constant force of 0.02, survival to 5 years is 0.9048 and to 10 years is 0.8187, and the difference is the chance of death between ages 45 and 50.

  1. A0.0861Correct
  2. B0.0950
  3. C0.1813
  4. D0.0905
  5. 0.0714

Explanation

Probability = 5p_5 ... precisely, P(5<T_40<=10) = e^{-0.02*5} - e^{-0.02*10} = e^{-0.1} - e^{-0.2} = 0.904837 - 0.818731 = 0.086106. Option 3 (0.0905) is e^{-0.1} approximately misapplied, and 0.1813 is the probability of death within 10 years.

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