Dear Petr,

 

I tried replying directly to you but my communication was rejected as spam.
On second thought, it is possible that it is.

 

Thank you very much for taking the time and interest to answer my enquiry to
the R Help Group. 

 

My interest isn’t so much in the particular data set as in how to conduct
such an analysis in R. The URL of the article where Bates was a coauthor
which describes the technique is
<http://jds.fass.org/cgi/content/abstract/75/2/580>
http://jds.fass.org/cgi/content/abstract/75/2/580

 

I enclose the IV Rabbit weight (age (a) in days, weight (w) in grams) data
set from Koops 1986:171 (citation given in the original communication). 

 

a          w

0          35

10        103

20        181

30        300

40        395

40        479

60        561

70        641

80        720

90        810

100      892

110      958

120      1013

130      1072

140      1118

150      1168

160      1195

170      1208

 

The published results are (Koops 1986:173)

 

Table 2: Constant estimates for the multiphasic growth curve

 

Data set           a1        b1        c1        a1        b2        c2
a3        b3        c3

Rabbit             198      .048     24.8     352      .025     82.7     62
.051     140.2

 

Constants ai is in grams and ci in days. Constants bi in 1/(age-units).

 

Table 3. Information about the fit in a stepwise procedure

 

Data set           number of        error     residual            R-square
Durbin-Watson

                        phases(n)         df        variance
statistic

Rabbit             1                      15        1268
.9928               .35

                        2                      12        97
.9996               1.39

                        3                      9          40
.9999               2.78

                        4                      6          47
.9999               3.19     

 

My question is if it is possible to effect a multiphasic analysis in R and
if so how? 

 

Thank you very much,

 

Peter B.

 

Laboratorio de Informática, Facultad de Medicina, UASLP, SLP, SLP, MEX

Departamento de Epidemiología Clínica, Facultad de Medicina, UASLP, SLP,
SLP, MEX

 

Peter B. Mandeville

cel:    444 860 3204

tel: 52 444 826 2346-49 ext 532

fax: 52 444 826 2350

 

P.D. Favor de confirmar la llegada de este correo. Gracias.

 


	[[alternative HTML version deleted]]

