Skip to content

IAI Actuarial Core Principles · Risk Modelling and Survival Analysis · Transition intensities dependent on age (exact or census)

Under a two-state model with constant force of mortality μ, a life aged x is observed for the whole of a one-year period. Which expression gives the probability that death occurs in the second half of the year (between t = 0.5 and t = 1)?

The probability is e^(-0.5μ) minus e^(-μ): survival to the half-year point less survival to the end of the year. The other options describe death in the first half or in the following year.

  1. Ae^(-0.5μ) - e^(-μ)Correct
  2. B1 - e^(-0.5μ)
  3. C0.5μ e^(-μ)
  4. De^(-μ) - e^(-2μ)
  5. μ e^(-0.5μ)

Explanation

Probability of death in (0.5, 1) = P(survive to 0.5) - P(survive to 1) = e^(-0.5μ) - e^(-μ). Option 1 is the probability of dying in the first half. Option 3 would be the second year.

Did you get it right without looking?

One question tells you little. A timed set on Transition intensities dependent on age (exact or census) shows your real accuracy, how long you take and where you lose marks.

More Transition intensities dependent on age (exact or census) questions