Question: A 1/2 replicate of a full 24 factorial experiment is to be conducted. Unfortunately, only four experimental runs can be made on a given day, and it is feared that important environmental variables may change from day to day and impact experimental results.
(a) Make an intelligent recommendation of which ABCD combinations to run on each of 2 consecutive days. Defend your answer. (You should probably think of "day" as a fifth factor and at least initially set things up as a 1/4 replicate of a full 25 factorial. Let the two generators be D↔ABC and E↔BC where E is (+) for day 2 and (-) for day 1.)
(b) Assuming that environmental changes do not interact with the experimental factors A through D, list the eight sets of aliases associated with your plan from (a). Your sets must include the main effects and interactions of A through D and the main effect (only) of E (day).
(c) Discuss how data analysis would proceed for your study.