Skip to content

IAI Actuarial Core Principles · Risk Modelling and Survival Analysis · Markov processes

A two-state Markov jump process has rate a from state 0 to 1 and rate b from 1 to 0, with a=0.3 and b=0.5. Starting in state 0, p_00(t) takes which form?

p_00(t) = 0.5/0.8 + (0.3/0.8) e^{-0.8t}. The limit is b/(a+b), the stationary probability of state 0, and the decay rate is a+b. It equals 1 at t=0, as required.

  1. A0.3/0.8 + (0.5/0.8) e^{-0.8t}
  2. B0.5/0.8 + (0.3/0.8) e^{-0.8t}Correct
  3. C0.5/0.8 + (0.3/0.8) e^{-0.2t}
  4. D0.3/0.8 + (0.5/0.8) e^{-0.2t}
  5. 0.5 + 0.3 e^{-0.8t}

Explanation

For a two-state chain, p_00(t) = b/(a+b) + a/(a+b) e^{-(a+b)t}. With a+b=0.8 this gives 0.5/0.8 + 0.3/0.8 e^{-0.8t}. At t=0 it equals 1, and as t grows it tends to 0.625. Option 0 swaps the constants and fails the stationary check.

Did you get it right without looking?

One question tells you little. A timed set on Markov processes shows your real accuracy, how long you take and where you lose marks.

More Markov processes questions