rpart.poisson {rpart}R Documentation

Set up for `poisson' Method for an Rpart Model

Description

Set up for poisson method for an rpart model.

Usage

rpart.poisson(y, offset, parms, wt)

Arguments

y the responses, a vector or a two-column matrix. If a matrix the first column is the observation times and the second is the counts.
offset an offset, or NULL. The offset is interpreted as a log observation time.
parms a list of parameters.
wt case weights.

Details

rpart.poisson is to be used only by the function rpart.

Value

Returns a list consisting of

y a matrix giving the observation times and number of events,
parms a named list of parameters, with components shrink and method (1 for "deviance", 2 for "sqrt"),
numresp the number of responses, here 2,
numy the number of columns in y, here 2,
summary a function to be invoked by summary.rpart,
text a function to be invoked by text.rpart.

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