Loading in 2 Seconds...
Loading in 2 Seconds...
The Essentials of 2-Level Design of Experiments Part II: The Essentials of Fractional Factorial Designs. Developed by Don Edwards, John Grego and James Lynch Center for Reliability and Quality Sciences Department of Statistics University of South Carolina 803-777-7800.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Developed by Don Edwards, John Grego and James LynchCenter for Reliability and Quality SciencesDepartment of StatisticsUniversity of South Carolina803-777-7800
The alias structure will be complicated for more parsimonious designs; we will add a few more guidelines for constructing alias tables later on.
*Example based on experiment by Pankaj Arora, a student in Statistics 506
The shortest word in the design generator has three letters, so we call this a Resolution III design
After computing the alias structure for main effects, it may require trial and error to find the remaining rows of the alias structure
We often exclude higher order terms from the alias structure (except for the design generator).
Computation of Factor Effects
The interaction is probably due to BC rather than DE
U-Do-It Exercise: What is the EMR if the experimenter wishes to minimize the corrosion rate?
U-Do-It Exercise Solution
A statistically-minded vegetarian* studied 5 factors that would affect the growth of alfalfa sprouts. Factors included measures such as presoak time and watering regimen. The response was biomass measured in grams after 48 hours. Factor D was assigned to the BC column and factor E was assigned to the ABC column in the 3-factor 8-run signs table.
*Suggested by a STAT 506 project, Spring 2000
The runs table appears below. Find the alias structure for this data and analyze the data.
The first two interaction terms we would normally try (AB and AC) had not yet appeared in the alias structure, which made the last two rows of the table easy to obtain.
Main effects are confounded with two way effects, making this a Resolution III design.
ANALYSIS--Computation of Factor Effects
ANALYSIS--Plot of Factor Effects