Machine-translated by Google. Questions are authored in English.
Top

Discussion

Consider the MC consisting of the three states 0, 1, 2 and having TPM :

\[ P = \begin{pmatrix} \frac{1}{2} & \frac{1}{2} & 0 \\ \frac{1}{2} & \frac{1}{4} & \frac{1}{4} \\ 0 & \frac{1}{3} & \frac{2}{3} \end{pmatrix} \]

Which of the following is correct ?

  • A.All states do not communicate
  • B.The stationary distribution does not exist
  • C.\(P_{00}^{(2)} = \dfrac{1}{4}\)
  • D.MC is irreducible

Answer: D

The correct statement is MC is irreducible.

From the matrix, state 0 goes to 1 (\(p_{01} = 1/2\)), 1 goes to 0 and to 2 (\(p_{10} = 1/2\), \(p_{12} = 1/4\)), and 2 goes to 1 (\(p_{21} = 1/3\)). So every state can reach every other through state 1: all states communicate and the chain is irreducible, which rules out A.

A finite irreducible chain has a unique stationary distribution, so B is false. And

\[ \begin{aligned} P_{00}^{(2)} &= \tfrac{1}{2} \cdot \tfrac{1}{2} + \tfrac{1}{2} \cdot \tfrac{1}{2} + 0 \\ &= \tfrac{1}{2} \end{aligned} \]

not 1/4, so C is false.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.