Bioequivalence and Bioavailability Forum • Least square mean

Least square mean [Software]

posted by d_labes – Berlin, Germany, 2008-05-28 18:35 (6593 d 05:23 ago) – Posting: # 1879
Views: 10,737

Dear HS, dear Yu,

I think it is necessary to have the concise context of the formulas before discussing in depth.

I do not own Equivtest. But a bet a big coin that because sequence means are mentioned and equivalence studies are mostly done with cross-over designs, that we are talking about the evaluation of such cross-over studies.

The formula
(x₁+x₂)/2
then looks to me as that what is called a 'Least square mean'.

Helmuts simple data give with


Proc GLM;

  class sequence;

  model numbers=sequence;

  estimate 'Overall LSMean' intercept 1;

run;



                          Standard

Parameter  Estimate         Error    t Value    Pr > |t|

------------------------------------------------------------

LSMean    3.25000000    0.41666667      7.80     0.0044

If the numbers are treatment differences in one subject, then the above code is for evaluation of the overall treatment difference in Senn's basic estimator approach.

Stephen Senn
Cross-over trials in clinical research
Wiley, 2002, chapter 3.

—
Regards,

Detlew

Complete thread:

Mean calculation method in unbalanced cross-over study yckim 2008-05-27 15:04 [Software]
- EquivTest v1 / v2 / PK Helmut 2008-05-27 15:41
  - EquivTest v1 / v2 / PK yckim 2008-05-28 01:39
    - Weighted mean Helmut 2008-05-28 11:55
      - Least square meand_labes 2008-05-28 16:35
        
        Least square mean yckim 2008-06-03 07:46
        
        Least square mean JPL 2008-06-03 09:10
        
        Least square mean vish14184 2008-06-04 06:54
        
        Least square mean JPL 2008-06-04 08:44