an object of class 'slim', usually, a result of a call to
'slim'.
parm
a specification of which parameters are to be given
confidence intervals, either a vector of numbers or a vector of
names. If missing, all parameters are considered.
level
the confidence level required.
empirical
logical indicating if empirical variances of y should be
used in estimating standard errors (the default). Empirical standard errors
should be used unless covariances have been well modelled.
...
arguments passed to or from other methods.
Value
A matrix (or vector) with columns giving lower and upper confidence
limits for each parameter.