[R-sig-ME] Arctic Nematode Growth Data

Douglas Bates bates at stat.wisc.edu
Thu Mar 26 18:15:16 CET 2009

On Wed, Mar 25, 2009 at 7:47 PM, Murray Jorgensen
<maj at stats.waikato.ac.nz> wrote:
> I thought some list members might appreciate the following data set as an
> example suitable for nonlinear mixed effects modelling. It is data from
> Dennis Proctor's PhD thesis which I came by 30 years ago but have only just
> fully entered onto the computer. Unfortunately I have lost touch with Dennis
> but I have no doubt that he would not object to fair usage provided
> attribution was made.

Thanks for sending the data, Murray.

> At each age there are 3 replicate groups of nematodes measured. Apparently
> the length measurement was destructive and no nematodes are multiply
> measured.

> The R code below reads the data into a data frame as well as creating some
> other structures of interest. I am well aware that constructing a vector by
> concatenation inside a loop is regarded as poor R style, but I could not
> remember what the approved alternative was!

unlist the result of apply

> str(unlist(apply(fr, 1, function(x) len[rep(1:27, x)])))
 num [1:1503] 0.22 0.26 0.26 0.26 0.26 0.3 0.3 0.3 0.3 0.3 ...

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