UNIVERSITY OF SOUTHAMPTON ECON6023W1 SEMESTER 1 EXAMINATIONS 2018-19 ECON6023 Macroeconomics Duration: 180 mins (3 HRS) This paper contains 4 questions Answer ALL questions in Section A and in Section B. Section A carries 1/2 of the total marks for the exam paper and you should aim to spend about 90 minutes on it. Section B carries 1/2 of the total marks for the exam paper and you should aim to spend about 90 minutes on it. An outline marking scheme is shown in brackets to the right of each question. Only University approved calculators may be used. A foreign language direct ‘Word to Word’ translation dictionary (paper version) ONLY is permitted. Provided it contains no notes, additions or annotations. Copyright 2019 v02 c © University of Southampton Page 1 of 6 2 ECON6023W1 Section A A1 (10 points) Consider a two-period (t=0,1) version of the neoclassical growth model: max(c0,c1,k1,k2){ln c0 + β ln c1}, where β ∈ (0, 1), subject to c0 + k1 = k α 0 , c1 + k2 = k α 1 , and c0, c1, k1, k2 ≥ 0, where α ∈ (0, 1) and k0 is given. Notation is as usual. (a) Derive the optimal decision rules for the capital stock and con- sumption in period t = 0. [5] (b) Derive the value function in period t = 0. [5] Copyright 2019 v02 © University of Southampton Page 2 of 6 3 ECON6023W1 A2 (15 points) Consider a Markov chain with the following transition matrix: P = [ 0.7 0.3 0.2 0.8 ] (a) Suppose that the unconditional distribution at time t over the 2 states of the Markov chain with this transition matrix is: pit = [ 0.75 0.25 ] [5]Find the unconditional distribution at time t + 1, pit+1. (b) Find the stationary distribution of this Markov chain. [10] Copyright 2019 v02 © University of Southampton TURN OVER Page 3 of 6 4 ECON6023W1 A3 (25 points) Consider a consumer with the following optimization problem: max {ct,at+1} ∞∑ t=0 βt ln(ct) s.t. ct + at+1 = Rat + w, t = 1, 2, . . . , where β ∈ (0, 1), ct is the consumer’s level of consumption in period t, at is the consumer’s asset holdings at the beginning of period t, R is the gross interest rate, and w is the consumer’s labour earnings in each period. (a) Formulate the consumer’s problem as a recursive problem. [5] (b) Use the “guess-and-verify” method to find the value function and the corresponding decision rules. (Hint: the value function in this problem takes the form v(a) = A+B ln(a+D), where A, B, D are coefficients to be solved for) [10] (c) Characterize the dynamics of the consumer’s asset holdings. Do they converge or diverge? If they converge, to what value do they converge? [10] Copyright 2019 v02 © University of Southampton Page 4 of 6 5 ECON6023W1 Section B Consider an economy inhabited by a continuum of identical house- holds and each household solves: max {ct,ht,it,kt+1}∞t=0 ∞∑ t=0 βt [u (ct) + v (1− ht)] , subject to ptbt+1 + ct + it = rt(1 − τk,t)kt + (1 − τw,t)wtht + bt and kt+1 = (1 − δ)kt + it. bt+1 is government debt which the government must pay back to the households in period t + 1. This asset is traded at period t at price pt. All other variables have the usual interpretation. In each period, tax revenues and government debt are used by the government to finance some exogenously given and constant government spending G. Perfectly competitive firms solve each period max kdt ,h d t [ Af (kdt , h d t )− rtkdt − wthdt ] , where kd and hd denote capital and labour demand. A ≥ 0 is a productivity parameter. Preferences and production function f have the usual neoclassical assumptions. β and δ ∈ (0, 1), and agents have rational expectations. (a) Find the first order conditions for the representative household and firm. [10] (b) Write down the problem of a benevolent planner. [10] (c) Find the first order conditions of a benevolent planner and ex- plain whether there is a market equilibrium with the same allo- cations. [10] (d) Write down the implementability constraints that a Ramsey plan- ner would take as given and explain why the solution to a Ramsey problem differs from that of a Planner problem. [10] Copyright 2019 v02 © University of Southampton TURN OVER Page 5 of 6 6 ECON6023W1 (e) Show the long run level of capital income taxes chosen by the Ramsey planner. [10] END OF PAPER Copyright 2019 v02 © University of Southampton Page 6 of 6 Social Sciences Examination Feedback 2018/2019 Module Code & Title: ECON6023 Macroeconomics Module Coordinator: Alessandro Mennuni and Serhiy Stepanchuk Mean Exam Score: 56.08 Percentage distribution across class marks: UG Modules 1 st (70% +) 2.1 (60-69%) 2.2 (50-59%) 3rd (40-49%) Fail (25-39%) Uncompensatable Fail (<25%) PGT Modules 70% + 25% 60-69% 25% 50-59% 25% <50% 25% Overall strengths of candidates’ answers: All students answered question A2(b) correctly. Most students also answered question A2(a) correctly. This shows their understanding of the properties of Markov chains. Most students answered correctly question A3(a), which demonstrates their ability to formulate recursively the dynamic optimization problems. The understanding of the Ramsey taxation was not great for many students. Besides the mathematics, some struggled with understanding the difference between a planner problem and a government that faces market constraints. Overall weaknesses of candidates’ answers: Very few students had a correct answer to question A3(c). This shows that their ability to apply the dynamic programming tools needs more work. Pattern of question choice: N/A Issues that arose with particular questions: N/A Further comments not covered above: N/A Discipline vetting completed By (Name): E Mentzakis Date:28 Feb 2019
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