Dataset: shoetreadfricton.csv

Source: M.G. Blanchette and C.M. Powers (2015). "The Influence of Footwear
Tread Groove Parameters on Available Friction," Applied Ergonomics,
Vol. 50, pp. 237-241.

Description: 3 Factor experiment relating coefficient of friction (COF)
to: 
groove orientation (1=oblique(angled), 2=perpendicular (side-to-side),
3=parallel (front to back))
groove width (3, 6, or 9 mm)
groove depth (2, 4, 6 mm)
1 replicate per treatment, n=27

Variables
runNum
COF
orient
width
depth