lr_betas | R Documentation |
Function lr_betas
obtains a Likelihood Ratio test, LR in what follows,
with the purpose of testing if some of the β coefficients in the G equations of the
SUR model are equal. This function has a straightforward application, especially when G=1,
to the case of testing for the existence of structural breaks in the β parameters.
The function can test for the homogeneity of only one coefficient, of a few of them or even the homogeneity of all the slope terms. The testing procedure implies, first, the estimation of both a constrained and a unconstrained model and, second, the comparison of the log-likelihoods to compute the LR statistics.
@usage lr_betas (obj, R, b)
lr_betas(obj, R, b)
obj |
An |
R |
A row vector of order (1xPr) showing the set of r linear constraints on the β parameters. The first restriction appears in the first K terms in R, the second restriction in the next K terms and so on. |
b |
A column vector of order (rx1) with the values of the linear restrictions on the β parameters. |
Object of htest
including the LR
statistic, the corresponding p-value, the degrees of
freedom and the values of the sample estimates.
Fernando Lopez | fernando.lopez@upct.es |
Roman Minguez | roman.minguez@uclm.es |
Jesus Mur | jmur@unizar.es |
Mur, J., Lopez, F., and Herrera, M. (2010). Testing for spatial effects in seemingly unrelated regressions. Spatial Economic Analysis, 5(4), 399-440. <doi:10.1080/17421772.2010.516443>
Minguez, R., Lopez, F.A. and Mur, J. (2022). spsur: An R Package for Dealing with Spatial Seemingly Unrelated Regression Models. Journal of Statistical Software, 104(11), 1–43. <doi:10.18637/jss.v104.i11>
spsurml
, spsurtime
, wald_betas
## VIP: The output of the whole set of the examples can be examined ## by executing demo(demo_lr_betas, package="spsur") #' ################################################# ######## CROSS SECTION DATA (G>1; Tm=1) ######## ################################################# #### Example 1: Spatial Phillips-Curve. Anselin (1988, p. 203) rm(list = ls()) # Clean memory data(spc) lwspc <- spdep::mat2listw(Wspc, style = "W") Tformula <- WAGE83 | WAGE81 ~ UN83 + NMR83 + SMSA | UN80 + NMR80 + SMSA ### H0: equal beta for SMSA in both equations. R <- matrix(c(0,0,0,1,0,0,0,-1), nrow=1) b <- matrix(0, ncol=1) spcsur.slm <- spsurml(formula = Tformula, data = spc, type = "slm", listw = lwspc) summary(spcsur.slm) lr_betas(spcsur.slm, R = R, b = b) ### Estimate restricted SUR-SLM model spcsur.slmr <- spsurml(formula = Tformula, data = spc, type = "slm", listw = lwspc, R = R, b = b) summary(spcsur.slmr)
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