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IB Mathematics: Applications and Interpretation HL · AHL 7: Markov Chains & Transition Matrices · AHL 7.3
Name Date
Steady state and long-term probabilities Problem set A
Use the calculator for powers of a matrix and for solving equations. Give exact answers as fractions when the question says exact, and other answers to 3 significant figures.
Difficulty: first skills applying them stretch
Skills
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\(\mathbf{T} = \begin{pmatrix} 0.67 & 0.14 & 0.19 \\ 0.21 & 0.79 & 0.28 \\ 0.12 & 0.07 & 0.53 \end{pmatrix}\) and \(\mathbf{s}_0 = \begin{pmatrix} 0.6 \\ 0.1 \\ 0.3 \end{pmatrix}\). Find \(\mathbf{T}^{50} \mathbf{s}_0\) and \(\mathbf{T}^{100} \mathbf{s}_0\). Use them to write down the long-term state vector.
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\(\mathbf{T} = \begin{pmatrix} 0.52 & 0.15 & 0.22 \\ 0.29 & 0.57 & 0.31 \\ 0.19 & 0.28 & 0.47 \end{pmatrix}\). The steady-state vector is \(\mathbf{s} = (s_1, s_2, s_3)\). Use \(\mathbf{T}\mathbf{s} = \mathbf{s}\) to write down a system of three linear equations that can be solved for \(s_1, s_2, s_3\). Do not solve it.
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Find the exact steady-state vector by setting up and solving a system of equations.
- (a) \(\mathbf{T} = \begin{pmatrix} 0.79 & 0.34 \\ 0.21 & 0.66 \end{pmatrix}\)
- (b) \(\mathbf{T} = \begin{pmatrix} 0.58 & 0.28 & 0.2 \\ 0.23 & 0.27 & 0.22 \\ 0.19 & 0.45 & 0.58 \end{pmatrix}\)
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Find the exact steady-state vector for \(\mathbf{T} = \begin{pmatrix} 0.06 & 0.34 & 0.5 & 0.4 \\ 0.08 & 0.22 & 0.04 & 0.12 \\ 0.44 & 0.04 & 0.36 & 0.22 \\ 0.42 & 0.4 & 0.1 & 0.26 \end{pmatrix}\).
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Use your calculator to find the steady-state vector. Give the entries to 3 significant figures.
- (a) \(\mathbf{T} = \begin{pmatrix} 0.74 & 0.07 & 0.09 \\ 0.14 & 0.87 & 0.13 \\ 0.12 & 0.06 & 0.78 \end{pmatrix}\)
- (b) \(\mathbf{T} = \begin{pmatrix} 0.38 & 0.04 & 0.22 & 0.04 \\ 0.16 & 0.02 & 0.1 & 0.5 \\ 0.4 & 0.44 & 0.48 & 0.2 \\ 0.06 & 0.5 & 0.2 & 0.26 \end{pmatrix}\)
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\(\mathbf{T} = \begin{pmatrix} 0.12 & 0.16 & 0.22 & 0.06 \\ 0.5 & 0.12 & 0.46 & 0.44 \\ 0.28 & 0.38 & 0.02 & 0.04 \\ 0.1 & 0.34 & 0.3 & 0.46 \end{pmatrix}\) and \(\mathbf{s}_0 = \begin{pmatrix} 0.25 \\ 0.25 \\ 0.4 \\ 0.1 \end{pmatrix}\). Find \(\mathbf{s}_5\).
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The transition matrix \(\mathbf{T} = \begin{pmatrix} 0.72 & 0.19 \\ 0.28 & 0.81 \end{pmatrix}\) gives the probability that a customer's next phone is made by Aero (A) or by Brio (B), with the brands in the order A, B. Write down the probability that a customer who now has a Brio phone buys an Aero phone next.
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Three types of land use, 1, 2 and 3, change each decade with transition matrix \(\mathbf{T} = \begin{pmatrix} 0.77 & 0.11 & 0.09 \\ 0.16 & 0.74 & 0.21 \\ 0.07 & 0.15 & 0.7 \end{pmatrix}\), in that order.
- (a) Find the long-term probability matrix, with entries to 3 significant figures.
- (b) Hence state the long-term percentage of type 2.
In context
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A hockey team wins (W) or does not win (N) each match. If it wins a match, the probability that it wins the next is 0.68. If it does not win a match, the probability that it wins the next is 0.37.
- (a) Write down the transition matrix.
- (b) The team did not win its last match. Find the probability that it wins its third match after that.
- (c) Find the exact steady-state vector, and state the long-term probability that the team wins a match.
Stretch
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\(\mathbf{T} = \begin{pmatrix} 0.74 & p \\ 0.26 & 1 − p \end{pmatrix}\) is a transition matrix with steady-state vector \(\mathbf{s} = \begin{pmatrix} 0.6 \\ 0.4 \end{pmatrix}\).
- (a) Use \(\mathbf{T}\mathbf{s} = \mathbf{s}\) to write down an equation for p.
- (b) Solve it to find p.
jmaths.xyz · AI HL · AHL 7.3 Steady state and long-term probabilities