broken.line | R Documentation |
Given a segmented model (typically returned by a segmented
method), broken.line
computes the fitted values (and relevant standard errors) for the specified ‘segmented’ relationship.
broken.line(ogg, term = NULL, link = TRUE, interc=TRUE, se.fit=TRUE, isV=FALSE,
.vcov=NULL, .coef=NULL, ...)
ogg |
A fitted object of class segmented (returned by any |
term |
Three options. i) A named list (whose name should be one of the segmented covariates in the model |
link |
Should the predictions be computed on the scale of the link function if |
interc |
Should the model intercept be added? (provided it exists). |
se.fit |
If |
isV |
A couple of logicals indicating if the segmented terms |
.vcov |
Optional. The full covariance matrix of estimates. If |
.coef |
The regression parameter estimates. If unspecified (i.e. |
... |
Additional arguments to be passed on to |
If term=NULL
or term
is a valid segmented covariate name,
predictions for that segmented variable are the relevant fitted values from the model. If term
is a (correctly named) list with numerical values, predictions corresponding to such specified values
are computed. If link=FALSE
and ogg
inherits from the class "glm", predictions and possible standard
errors are returned on the response scale. The standard errors come from the Delta method.
Argument link
is ignored whether ogg
does not inherit from the class "glm".
A list having one component if (if se.fit=FALSE
), and two components (if se.fit=TRUE
) list representing predictions and standard errors for the segmented covariate values.
This function was written when there was not predict.segmented
(which is more general).
Vito M. R. Muggeo
segmented
, predict.segmented
, plot.segmented
, vcov.segmented
set.seed(1234)
z<-runif(100)
y<-rpois(100,exp(2+1.8*pmax(z-.6,0)))
o<-glm(y~z,family=poisson)
o.seg<-segmented(o,seg.Z=~z)
## Not run: plot(z,y)
## Not run: points(z,broken.line(o.seg,link=FALSE)$fit,col=2) #ok, but use plot.segmented()!
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