nobs {stats} | R Documentation |
Extract the number of ‘observations’ from a model fit. This is
principally intended to be used in computing BIC (see AIC
).
nobs(object, ...) ## Default S3 method: nobs(object, use.fallback = FALSE, ...)
object |
A fitted model object. |
use.fallback |
logical: should fallback methods be used to try to guess the value? |
... |
Further arguments to be passed to methods. |
This is a generic function, with an S4 generic in package stats4.
There are methods in this package for objects of classes
"lm"
, "glm"
, "nls"
and
"logLik"
, as well as a default method (which throws an
error, unless use.fallback = TRUE
when it looks for
weights
and residuals
components – use with care!).
The main usage is in determining the appropriate penalty for BIC, but
nobs
is also use by the stepwise fitting methods
step
, add1
and drop1
as a
quick check that different fits have been fitted to the same set of
data (and not, say, that further rows have been dropped because of NAs
in the new predictors).
A single number, normally an integer. Could be NA
.
AIC
.