Nested-factorial example
Student experiment (Yu-Pei Chang): A study of toy cars
Response
Distance (in cm) traveled until car comes to a stop.
Primary factors
- ramp: A ramp is in fact a 3-ring binder. One, two, or three
1-inch binders are stacked.
- car: Two different toy cars are studied: a large and a small one.
Our initial goal is to be able to detect variations of plus or minus 10 cm.
(effect-size SD = 5 cm).
Random factors
- TRIAL(ramp):
The two cars are run together down a ramp of a certain slope.
Estimated SD (based on pilot data) is 7.4
- RESIDUAL = car*TRIAL(ramp):
Estimated SD is 11.0