| getContrasts {gnm} | R Documentation |
For each set in a specified list of sets of parameters from a
gnm model, computes the estimated simple contrasts (i.e.,
differences) with the last parameter in the set, and estimated standard
errors for those estimated differences.
getContrasts(model, sets = NULL, nSets = 1, ...)
model |
a model object of class "gnm" |
sets |
a vector of indices (if nSets is 1) or
a list (of length nSets) of such vectors |
nSets |
the number of vectors of indices to use |
... |
arguments to pass to other functions |
The indices must all be in 1:length(coef(object)). If
sets = NULL, a Tk dialog is presented for the selection
of indices (model coefficients).
For each set of coefficients selected, differences with the last coefficient and their standard errors are computed. A check is performed first on the estimability of all such differences.
A list (of length nSets) of data frames, each containing variables
estimate and se
David Firth
set.seed(1)
data(yaish)
## Fit the "UNIDIFF" mobility model across education levels
unidiff <- gnm(Freq ~ educ:orig + educ:dest +
Mult(Exp(-1 + educ), orig:dest), family = poisson,
data = yaish)
## Examine the education multipliers (differences on the log scale):
getContrasts(unidiff, grep("Mult1.Factor1", names(coef(unidiff))))