extend {simr} | R Documentation |
Extend a longitudinal model.
Description
This method increases the sample size for a model.
Usage
extend(object, along, within, n, values)
Arguments
object |
a fitted model object to extend. |
along |
the name of an explanatory variable. This variable will have its number of levels extended. |
within |
names of grouping variables, separated by "+" or ",". Each combination of groups will be
extended to |
n |
number of levels: the levels of the explanatory variable will be replaced by |
values |
alternatively, you can specify a new set of levels for the explanatory variable. |
Details
extend
takes "slices" through the data for each unique value of the extended variable.
An extended dataset is built from n
slices, with slices duplicated if necessary.
Value
A copy of object
suitable for doSim
with an extended dataset attached as
an attribute named newData
.
Examples
fm <- lmer(y ~ x + (1|g), data=simdata)
nrow(example)
fmx1 <- extend(fm, along="x", n=20)
nrow(getData(fmx1))
fmx2 <- extend(fm, along="x", values=c(1,2,4,8,16))
nrow(getData(fmx2))