48 Methodology of Empirical Econometric Modeling
1920 1940 1960 1980
–12.5
–12.0 a ef^
e
1920 1940 1960 1980
–0.25
0.00
b pf−p
1920 1940 1960 1980
–11.5
–11.0
–10.5
–10.0 c
1920 1940 1960 1980
0.0
0.1
0.2
0.3
d s
1920 1940 1960 1980
–0.1
0.0
0.1 e Δef
1920 1940 1960 1980
1.0
1.2
1.4
1.6 f
log family size
Figure 1.6 Food expenditure and related time series
ona, and was selected by Autometrics at 1% for all candidate variables, including
impulse saturation. All diagnostic tests were insignificant, and the PcGive unit root
test strongly rejected the null of no cointegration (tur=−11.37∗∗: (see Banerjee
and Hendry, 1992; Ericsson and MacKinnon, 2002) with the long-run solution:
c 0 =ef+7.99−0.4e+0.36(pf−p). (1.39)
Transforming to differences and the equilibrium-correction term from (1.39),
Autometrics selected over 1931–89 (at 2.5%, again including impulse saturation):
ef,t= 0.34
(0.02)
st− 1 − 0.32
(0.02)
c0,t− 1 + 0.67
(0.04)
et+ 0.13
(0.03)
et− 1
− 0.64
(0.03)
(pf−p)t− 0.09
(0.01)
I 31 − 0.10
(0.01)
I 32 + 0.04
(0.01)
I 34
+ 0.03
(0.01)
I 41 + 0.05
(0.01)
I 42 + 0.03
(0.01)
I 51 + 0.02
(0.01)
I 52 + 0.03
(0.01)
I 70
(
R∗
) 2
=0.96FM(13, 45)=94.9∗∗̂σ=0.0078Far(2, 44)=1.34
χ^2 (^2 )=1.04Farch(1, 44)=2.25Freset(1, 45)=0.35
Fhet(18, 27)=0.48FChow(9, 37)=0.99. (1.40)