Bioequivalence and Bioavailability Forum

model matrix and lexer [General Sta­tis­tics]

posted by d_labes  – Berlin, Germany, 2014-05-08 10:38 (3634 d 20:36 ago) – Posting: # 12927
Views: 5,807

Dear Ol'Pirate!

You really mean that the solution depends on the order of the effects in the model?
Just a quick check:
My above cited df's in R were obtained with
lm(log(AUC)~ tmt + period + subject, data=pair).
Now applying
lm(log(AUC)~ subject + tmt + period, data=pair)
gives:
       A vs D
       C vs D  B vs D
 subject 11      11
 tmt      1       1
 period   3       2
 Mserr    8       9

Seems you are correct! But IMHO this is not a good behavior.

BTW: R and SAS now coincide althoug in SAS the equivalent of the first lm() call was used.
The question is left: Why to hell are the df's different between the pairs?

Complete thread:

• df peculiarities for 4x4 crossover and EMA d_labes 2014-05-06 11:28 [General Sta­tis­tics] 
  • df peculiarities for 4x4 crossover and EMA - follow-up d_labes 2014-05-07 11:43
    • Mirror, mirror on the wall… Helmut 2014-05-07 16:49
      • … Snow White or Little Red Riding Hood? d_labes 2014-05-08 09:18
  • model matrix and lexer ElMaestro 2014-05-08 00:52
    • model matrix and lexerd_labes 2014-05-08 08:38