J. Carlos Escanciano and Ignacio N. Lobato 993
0 5 10 15 20 25 30 35
–0.2
0
0.1
0.2
Autocorrelogram
Lag j
0 5 10 15 20 25 30 35
0
0.5
1
1.5
2
Nonlinear IPRF plot
Lag j
r(
j)
KS (
j)
–0.1
Figure 20.8 IPRF for the weekly pound
Top graph is the heteroskedasticity robust autocorrelation plot. Bottom graph is the IPRF plot.
and:
̂f0,w(&,x)=^1
2 π
̂γ0,w(x),
to test the MDH, wherek(·)is a symmetric kernel andpa bandwidth parameter. He
considered a standardization of anL 2 -distance using a weighting functionW(·):
L^2 2,n(p)=
π
2
∫
R
∫π
−π
n
∣∣
∣̂fw(&,x)−̂f0,w(&,x)
∣∣
∣
2
W(dx)d& (20.9)
=
n∑− 1
j= 1
(n−j)k^2
(
j
p
)∫
R
∣∣
∣̂γj,w(x)
∣∣
∣
2
W(dx).
Under the null of MDH and some additional assumptions, Hong and Lee (2005)
showed that a convenient standardization ofL^2 2,n(p)converges to a standard nor-
mal random variable. The centering and scaling factors in this standardization
depend on the higher dependence structure of the series.
Alternatively, the generalized spectral distribution function is:
Hw(λ,x)= 2
λπ∫
0
fw(&,x)d&λ∈[0, 1],