Talk:Fractional factorial design

Context Needed

This article needs going over and context added. For example, it talks about "case III" and "resolution III, IV, and V" without any indication as to what these terms mean. -- 21:03, 27 January 2007 (UTC)

effect multiplication needs explaining

This concept is crucial to understanding what a defining relation is and how it is derived. But it is not explained (how does D=A*B imply I=ABD?). I have done some tweaks in other ways but may revisit this soon. Feel free to beat me to it. Baccyak4H (Yak!) 17:13, 23 August 2007 (UTC)

Factorial designs using the + and - convention for the two levels make effect multiplication rules intuitive. 830199wk (talk) 04:56, 27 October 2016 (UTC)From a user's perspective, any factor interracting with itself generates 1 (or I in this essay) :

              e.g. if the pattern (total of 4 experiments)  for factor 'd'   is (-,-,+,+), 
       then the effect "product"  dd  = (-,-,+,+)(-,-,+,+)=(+,+,+,+) = I ).   

e.g The defining relation for generator e, where e is confounded with the 4-level interraction,

                               e=abcd 

is I = ee = eabcd , or I = abcde . — Preceding unsigned comment added by 830199wk (talk • contribs) 11:31, 26 October 2016 (UTC)