Skip to content

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

A chain on {A,B,C} has P(A→B)=1, P(B→A)=0.5, P(B→C)=0.5, P(C→A)=1. What is the stationary probability of state A?

The stationary probability of A is 0.4. Since A moves only to B, πB = πA, and C is reached only from B with probability 0.5, so πC = 0.5πA. Normalising 2.5πA = 1 gives πA = 0.4.

  1. A1/3
  2. B0.4
  3. C0.5Correct
  4. D0.6
  5. 2/3

Explanation

Equations: πB=πA, πC=0.5πB, and πA=0.5πB+πC. So πB=πA and πC=0.5πA. Sum: πA(1+1+0.5)=1 gives πA=0.4. Check: 0.5×0.4+0.2=0.4. So 0.4, not 0.5.

Did you get it right without looking?

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

More Markov chains questions