interplinear: A function to provide estimates of the response for a
longitudinal data object. The estimate is obtained by linear
interpolation from the preceding and following observations.
Description
A linear interpolation, using approx, is used to obtain
estimates of the covariate at times other than those observed.
Usage
interplinear(x, ...)
"interplinear"(x, time, cov = NULL, ...)
"interplinear"(x, ...)
Arguments
x
The lgtdl object that is to be interpolated.
time
The time(s) at which interpolation is desired.
cov
The name of the covariate in the lgtdl object on
which the interpolation should be based. It is not required if there
is only one covariate.
...
Ignored.
Value
A vector containing the interpolated estimates of the covariate values
at the requested times.