statistical analysis of William's Design [Study As­sess­ment]

posted by Helmut Homepage – Vienna, Austria, 2022-02-11 20:07 (349 d 03:04 ago) – Posting: # 22774
Views: 1,390

Hi Ahmed,

❝ […] William's design (3 treatment, 3 period, 6 sequence), 2 test products against one reference. I analyzed the data as 3-way, and also separated the test products, each with a reference, and analyzed them. My question: should I get the same result?


Extremely unlikely. In the separate evaluations (as Incomplete Block Designs) you get two estimates of the within-subject variances (one in the comparison of T1 vs R and the other in the comparison of T2 vs R). Even if they would be identical, you have different degrees of freedom in the analyses. In each of the IBDs you have \(\small{df=n-2}\) and in the pooled ANOVA \(\small{df=2\times n-4}\), where \(\small{n}\) is the total number of subjects. Although the point estimates might be the same, the confidence intervals will not.

Dif-tor heh smusma 🖖🏼 Довге життя Україна! [image]
Helmut Schütz
[image]

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

UA Flag
Activity
 Admin contact
22,477 posts in 4,708 threads, 1,603 registered users;
21 visitors (0 registered, 21 guests [including 14 identified bots]).
Forum time: 23:11 CET (Europe/Vienna)

We must be careful not to confuse data with the abstractions
we use to analyze them.    William James

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5