Bioequivalence and Bioavailability Forum

To Err is Human [General Sta­tis­tics]

posted by d_labes  – Berlin, Germany, 2010-07-13 13:51 (5821 d 05:52 ago) – Posting: # 5614
Views: 17,201

"Good-Nature and Good-Sense must ever join;
To err is human, to forgive divine."
Alexander Pope (1688-1744)

Hi Paolo,
after looking at your data and your code some observations:

• Your implementation of the intra-subject contrast T-R (ilat in the guidance) is faulty. You must calculate T-0.5(R1+R2).
  
  
• The SAS code given in the guidance is half-cooked. See here and here.
  First: To get a 95% upper CI of the scaled ABE criterion IMHO you must use alpha=0.05 in the intermediate analysis of ilat.
  
  
• Second: The ominous x in the IGLM2 part of the code is IMHO wrong. What wee need here is (Y_T-Y_R)² and this would translate to me to x=estimate**2 in the SAS code.
  
  
• Third: The output in dglm1 from the intermediate analysis of (R1-R2) contains 3 rows of the ANOVA. We need only the row with the error term. Add a where source="Error"; in the corresponding datastep to calculate s_WR.
  Regarding the value for that I don't find an error. So dispute with your teacher .
  
  
• Try to check your SAS results (validate ) by implementing the necessary formulas from scratch f.i. in R. See here for some useful code snippets.
  

Hope this helps.

BTW: Can you tell us where the data came from?
And from where your teacher knows the solution?

Complete thread:

• SABE Reference Variability and CI Computation preyes323 2010-07-12 17:12 
  • Dataset Helmut 2010-07-12 17:26
    • Dataset preyes323 2010-07-12 18:20
      • Data format Helmut 2010-07-12 18:38
        • Data format preyes323 2010-07-13 01:16
          • SAS and/or Phoenix/WinNonlin-experts around? Helmut 2010-07-13 02:29
            • Phoenix/WinNonlin-experts around? d_labes 2010-07-13 12:15
              • Phoenix/WinNonlin-experts around? Helmut 2010-07-13 13:42
                • Mixed interest d_labes 2010-07-13 15:11
                  • Mixed interest Helmut 2010-07-13 19:19
                    • lme() answer and beyond ... d_labes 2010-07-14 10:41
                      • lme() answer and beyond ... Helmut 2010-07-14 13:47
                        • AIC, BIC and that all ... d_labes 2010-07-15 12:01
          • To Err is Humand_labes 2010-07-13 11:51
            • To Err is Human, but... Helmut 2010-07-13 13:45
              • ... to Arr is Pirate d_labes 2010-07-13 15:47
                • Brilliant page!!! ElMaestro 2010-07-14 21:03
            • To Err is Human preyes323 2010-07-14 14:45
              • Heads up! Helmut 2010-07-14 15:17
              • To Err is Teacher d_labes 2010-07-15 11:05
            • To Err is Human preyes323 2010-07-16 02:28
              • To Err is Human d_labes 2010-07-16 10:42
                • To Err is Human preyes323 2010-07-17 11:14
                  • Regulatory constants d_labes 2010-07-19 10:00
          • Data format ElMaestro 2011-02-06 11:54
            • SAS System Viewer Helmut 2011-02-06 13:02