prab.sarestimate {prabclus} | R Documentation |
This is either an interface for the function errorsarlm
for abundance data stored in an object of class prab
implemented for use in abundtest
, or, in case that spatial
information should be ignored, it estimates a two-way additive
unreplicated linear
model for log-abundances on factors species and region.
prab.sarestimate(abmat, prab01=NULL,sarmethod="eigen", weightstyle="C", quiet=TRUE, sar=TRUE, add.lmobject=TRUE)
abmat |
object of class prab . |
prab01 |
presence-absence matrix of same dimensions than the
abundance matrix of prabobj . This specifies the presences and
absences on which the presence/absence step of abundance-based tests
is based (see details). If NULL (which is usually the only
reasonable choice), prab01 is computed in order to indicate
the nonzeroes of prabobj$prab . |
sarmethod |
this is passed on as parameter method to
errorsarlm and documented there. We don't have
experience with any other choice than "eigen" . |
weightstyle |
can take values "W", "B", "C", "U", and "S" though tests
suggest that "C" should be chosen. See nb2listw . |
quiet |
this is passed on as parameter quiet to
errorsarlm and documented there. |
sar |
logical. If TRUE , a simultaneous autoregression
model is fitted by calling errorsarlm . If
FALSE , a two-way additive
unreplicated linear
model for log-abundances on factors species and region is computed
by lm ,
ignoring the spatial arrangement of the regions. |
add.lmobject |
logical. If TRUE , the whole output object
of errorsarlm (or lm ) is given out. |
A list with the following components:
sar |
see above. |
intercept |
numeric. Estimator of the intercept. |
sigma |
numeric. Estimator of error standard deviation. |
regeffects |
numeric vector. Estimator for region effects. |
speceffects |
numeric vector. Estimator for species effects. |
lamda |
numeric. Governs the degree of spatial
autocorrelation. See errorsarlm . |
size |
integer. Length of neighborhood list generated by
nb2listw used by
errorsarlm . |
nbweight |
numeric. Average weight of neighbors. |
lmobject |
if add.lmobject=TRUE , output object of either
lm or errorsarlm . |
Christian Hennig chrish@stats.ucl.ac.uk http://www.homepages.ucl.ac.uk/~ucakche
data(siskiyou) x <- prabinit(prabmatrix=siskiyou, neighborhood=siskiyou.nb, distance="none") # Not run; this needs package spdep # prab.sarestimate(x) prab.sarestimate(x, sar=FALSE)