PharmPK Discussion - When we can use SAS PROC GLM and SAS PROC MIXED

• On 6 Aug 2004 at 10:05:00, "Kanimozhi" (kanimozhi.-at-.gvkbio.com) sent the message
  

  Dear all,
  When we can use SAS PROC GLM and SAS PROC MIXED
  PROC GLM:
  When the design of the study is 2*2 3*3.
  PROC MIXED:
  When the design of the study is replicated.
  It will be nice any one could suggest me that am I correct or not.
  Thanking you,
  kanimozhi.A
  

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• On 6 Aug 2004 at 10:35:27, "Bonate, Peter" (pbonate.-at-.ilexonc.com) sent the message
  

  
  Replication has nothing to do with whether to use GLM or Mixed.  If the
  data are complete and no missing data then either can be used, although
  GLM will be faster.  GLM uses an exact solution to the linear system of
  equations, whereas Mixed uses an iterative process.  If the data are
  unbalanced and you have missing data then Mixed is the way to go because
  of the way missing data are handled with GLM.  GLM, I believe, deletes
  the entire subject from an analysis if that person has any missing data,
  but Mixed does not.  You are also more restricted with GLM in that
  compound symmetry is assumed.  With Mixed this assumption is relaxed and
  more generalized covariance matrices can be used.
  Also, the BE statistical guidance used Mixed as an example, not GLM.
  Hope this helps,
  Pete bonate
  

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