CH.test {uroot} | R Documentation |
This function computes the Canova-Hansen statistic for testing the null hypothesis of stationary seasonal cycles against the alternative of seasonal unit roots.
CH.test (wts, frec=NULL, f0=1, DetTr=FALSE, ltrunc=NULL)
wts |
a univariate time series object. |
frec |
a vector indicating the cycles to analyse. By default, all seasonal cycles are tested. |
f0 |
a 0-1 (No-Yes) vector of length one indicating wether a first lag of the dependent variable is included or not in the auxiliar regression. See details. |
DetTr |
a logical argument. If TRUE a linear trend is included in the auxiliar regression. |
ltrunc |
lag truncation parameter for computing the residuals covariance matrix. By default, round(s*(N/100)^0.25), where eqn{s} is the periodicity of the data and N the number of observations. |
Elements of frec
must be set equal to 0 if the season assigned to this element is not considered
and equals to 1 for the frequencies to analyse. The position of each frequency in the vector is as
follows: c(pi/2, pi) for quarterly series and c(pi/6, pi/3, pi/2, 2pi/3, 5pi/6, pi) for monthly series.
An object of class chstat-class
.
Javier López-de-Lacalle javlacalle@yahoo.es and Ignacio Díaz-Emparanza Ignacio.Diaz-Emparanza@ehu.es.
F. Canova and B.E. Hansen (1995), Are seasonal patterns constant over time? A test for seasonal stability. Journal of Business and Economic Statistics, 13, 237-252.
## CH test data(AirPassengers) ## Test for stationary cycles at all seasonal frequencies, ## including a first order lag and but not a linear trend. ch.out1 <- CH.test(wts=AirPassengers, frec=c(1,1,1,1,1,1), f0=1, DetTr=FALSE) ch.out1 ## Test for stationary seasonal cycles at frequencies +i and -i, ## including a first order lag and but not a linear trend. ch.out2 <- CH.test(wts=AirPassengers, frec=c(0,0,0,0,0,1), f0=1, DetTr=FALSE) ch.out2