Bioequivalence and Bioavailability Forum • Sum of residuals ~ ε

Sum of residuals ~ ε [Design Issues]

posted by ElMaestro – Denmark, 2019-12-24 15:10 (430 d 10:12 ago) – Posting: # 21027
Views: 3,224

Hi both,

» I disagree. In the model ε = 0. However in the fit, the sum of residuals is only asymptotically 0. We shouldn’t speak of bias when we obtain something sufficiently close to the numeric resolution of the machine.

Perhaps I am getting it wrong; the sentence above sounds a little off and I have a feeling you may not be discussing the same thing?

The sum of residuals for a fitted normal linear model will be zero. Not asymptotically. If you sum them in R or any other software you will get zero, be it either like zero-zero or effectively zero, depending on the implementation.
This is because the underlying assumption is that epsilon be distributed with mean zero. If we end up with a non-zero sum, I'd say we have screwed up somewhere.

Try sum(resid(M))

—
Pass or fail!
ElMaestro

Complete thread:

Should those subjects have only one period data be included in BE analysis? ssussu 2019-12-06 10:58 [Design Issues]
- No way! But... Beholder 2019-12-06 12:36
  - No way! But... ElMaestro 2019-12-06 13:14
    - No way! But... Helmut 2019-12-06 14:47
      - No way! But... PharmCat 2019-12-06 23:46
        
        No way! But... wienui 2019-12-07 04:01
        
        EMA guideline: no way...: mittyri 2019-12-07 20:58
        
        EMA guideline: no way...: wienui 2019-12-09 05:25
        
        Slightly off topic, but related :-) ElMaestro 2019-12-08 01:31
        
        Slightly off topic, but related :-) Shuanghe 2019-12-09 12:00
        Slightly off topic, but related :-) PharmCat 2019-12-09 15:13
        
        Slightly off topic, but related :-) ElMaestro 2019-12-21 15:02
        
        Slightly off topic, but related :-) PharmCat 2019-12-22 01:12
        2.220446e-16 ≈ 0 Helmut 2019-12-22 10:37
        
        The optional tolerance argument ElMaestro 2019-12-23 14:37
        2.220446e-16 ≈ 0 PharmCat 2019-12-24 14:18
        
        Sum of residuals ~ ε Helmut 2019-12-24 14:54
        
        Sum of residuals ~ εElMaestro 2019-12-24 15:10
        
        Wrong terminology Helmut 2019-12-28 13:55
        
        Sum of residuals ~ ε PharmCat 2019-12-24 18:40