An object returned from either class
tssem1FEM, class tssem1FEM.cluster, class tssem1REM,
class wls, class wls.cluster, class meta, class
reml or class MxRAMModel
select
Select all for both fixed- and random-effects parameters, fixed for the
fixed-effects parameters or random for the random-effects
parameters. For meta3X objects, allX is used to extract
all parameters including the predictors and auxiliary variables.