[R] PBIB datataset

(Ted Harding) Ted.Harding at nessie.mcc.ac.uk
Mon Dec 20 22:29:07 CET 2004

On 20-Dec-04 Douglas Bates wrote:
> This is a new version of SASmixed that was uploaded a couple of days 
> ago.  I changed it so that the fits are done with the lme4 version of 
> lme.  It should be faster and more reliable than the version of lme in 
> the nlme package.
> This version of SASmixed has a vignette that provides comparative 
> analyses in lme for the examples in "SAS System for Mixed Models".  The
> specification of models in the new lme is occasionally different from 
> the older specification.  Don't pay too much attention to the textual 
> descriptions - look at the examples in the appendices.  I haven't 
> finished rewriting the textual description from an old, old version.
> Those who (like me) cringe at the way that models with crossed random 
> effects needed to be specified in the old lme may find it interesting 
> that the Demand example now specifies the model fit as
> Demand> fm1Demand <- lme(log(d) ~ log(y) + log(rd) + log(rt) +
>      log(rs), data = Demand, random = list(State = ~1, Year = ~1))
> [...]
> The lme4 and nlme packages should not be loaded simultaneously.
> Use one or the other but not both.

Thanks a lot for these clarifications. This still leaves me with
a question or two.

Suppose I want (as I do) to work through Pinheiro & Bates, example
by example. Some datasets are here (lme4), others there (SASmixed,
nlme), etc.

Does this mean I need to start afresh, loading just the package
with the dataset currently of interest?

I'm a touch confused about the distribution (a) of datasets,
(b) of the R functions needed to analyse them according to
Pinheiro & Bates, over the packages! If I load the package
containing dataset A, will it include the functions used in
P&B for that dataset? Or might I need to load another one
as well? and, if so, might I encounter the sort of clash
you hint at above?

(I know I could probably check it in detail in each case as
it arises, but I guess you know your way arond all this better
than someone who hasn't been there yet).

With thanks (and congratulations on what looks like a very
well conceived book on the topic),

E-Mail: (Ted Harding) <Ted.Harding at nessie.mcc.ac.uk>
Fax-to-email: +44 (0)870 094 0861  [NB: New number!]
Date: 20-Dec-04                                       Time: 21:29:07
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