Calculates the design vector as required to generate the lsmean
and standard error. ls_design_equal
calculates it by
applying an equal weight per covariate combination whilst
ls_design_proportional
applies weighting proportional
to the frequency in which the covariate combination occurred
in the actual dataset.
ls_design_equal(data, frm, fix)ls_design_counterfactual(data, frm, fix)
ls_design_proportional(data, frm, fix)
A data.frame
Formula used to fit the original model
A named list of variables with fixed values