QUESTION 4 [20 marks]
(a) What is the difference between a static and a dynamic model?
[2]
(b) State an AR(2) model using the variable GDP.
[2]
(c) State a distributed lag model (OLM) using variable GDP.
[2]
(d) State the Auto Regressive Distributed Lag Model (ARDL) using the variable
GDP and gross fixed capital formation (GFCF), where GDP is the dependent
variable.
[4]
(e) Given the following ARDL equation:
GDPc= a 0 + a 1 GDPc-i + {30 PCEc+ {31PCEc-i + 00 PDic + 01PDlc
i. State all the short-run impact multipliers.
[2]
ii. What are the short-run impact multipliers associated with PCE and
POI?
[2]
iii. What are the cumulative short-run multipliers of PCE and POI after one
period?
[4]
iv. Determine the long-run multipliers with respect to PCE and POI.
[2]
QUESTION 5 [20 Marks]
(a) Interpret the unit root tests in the Tables (i) and (ii) below.
[5]
(b) Write down the equation employed to do these tests.
[5]
Null Hypothesis: GDP has a unit root
Exogenous: Constant, Linear Trend
Augmented Dickey-Fuller test statistic
Test critical values: 1% level
5% level
10% level
*MacKinnon (1996) one-sided p-values.
ii
Null Hypothesis: D(GDP) has a unit root
Exogenous: Constant, Linear Trend
Augmented Dickey-Fuller test statistic
Test critical values:
1% level
5% level
10% level
*MacKinnon (1996) one-sided p-values.
t-Statistic
-0.044739
-4.309824
-3.574244
-3.221728
Prob.*
0.9934
t-Statistic
-3.819094
-4.323979
-3.580622
-3.225334
Prob.*
0.0304
3