Bioequivalence and Bioavailability Forum • confint() for difference of effect levels

confint() for difference of effect levels [R for BE/BA]

posted by d_labes - Berlin, Germany, 2017-08-29 12:23 - Posting: # 17749
Views: 548

Dear Öberster Größter Meister,

» let us say we have an lm object for a BE analysis in a study where we have n treatments.
Ok. I assume we have.

» Is there a way to use confint() to derive CI's for the difference of the i'th and j'th treatments (where obviously i!=j, and i is within 1..n and j is within 1..n) ?
No. confint() gives you confidence intervals for the model parameters only.

» If not, is there another built-in function that achieves this goal?
Built in I know of none, if you mean a base R installation. Only from add-on packages.
Have a look at package multcomp.
Or if you prefer using such beasts like "least square means" have a look at package lsmeans.

BTW: All-at-once is not the preferred method of a big regulatory body.
Pairwise lm objects (throwing away the data under those treatments not under consideration) will give you the opportunity to use confint() to derive CI's.

—
Regards,

Detlew

Complete thread:

confint() for difference of effect levels - ElMaestro, 2017-08-29 10:20 [R for BE/BA]
- confint() for difference of effect levels - d_labes, 2017-08-29 12:23
  - confint() for difference of effect levels - ElMaestro, 2017-08-29 14:45
    - Homecooked solution? - ElMaestro, 2017-08-29 23:18
      - Restaurant solution - mittyri, 2017-08-30 08:11
        
        Great - ElMaestro, 2017-08-30 09:27
    - All-at-once or Two-at-a-time - d_labes, 2017-08-30 19:55