Laundry experiment example
Student experiment (Kazi Alward):
A study of shrinkage of cloth due to dryer temperature.
Response
Amount of shrinkage (in eighths of inches), sum of
length and width losses.
Primary factors
- heat: None, low, high (settings on dryer).
- cloth: Terry, flannel, broadcloth.
Our initial goal is to be able to detect variations
of plus or minus 4/8 = .5 in.
(effect-size SD = 2/8 in).
Random factors
- LOAD(heat):
Samples of all types of washed cloth are dried together
in one load.
Estimated SD (based on pilot data) is 2.1
- cloth*LOAD(heat):
Variations among loads at the same heat on the same type of cloth.
Estimated SD is 1.3
- RESIDUAL = SAMPLE(cloth*LOAD(heat)): estimated SD is 1.2