object
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an object representing a model of an appropriate class.
This is used as the initial model in the stepwise search.
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scope
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defines the range of models examined in the stepwise search.
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scale
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used in the definition of the AIC statistic for selecting the models,
currently only for lm , aov and glm models.
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direction
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the mode of stepwise search, can be one of "both" , "backward" ,
or "forward" , with a default of "both" .
If the scope argument is missing,
the default for direction is "backward" .
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trace
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if positive, information is printed during the running of stepAIC() .
Larger values may give more information on the fitting process.
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keep
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a filter function whose input is a fitted model object and the
associated AIC statistic, and whose output is arbitrary.
Typically keep will select a subset of the components of
the object and return them. The default is not to keep anything.
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steps
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the maximum number of steps to be considered. The default is 1000
(essentially as many as required). It is typically used to stop the
process early.
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use.start
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if true the updated fits are done starting at the linear predictor for
the currently selected model. This may speed up the iterative
calculations for glm (and other fits), but it can also slow them
down.
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k
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the multiple of the number of degrees of freedom used for the penalty.
Only k=2 gives the genuine AIC: k = log(n) is sometimes referred
to as BIC or SBC.
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...
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any additional arguments to extractAIC .
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