A full factorial experiment with four factors run by a golf enthusiast. The objective of the experiments was for the golfer to maximize her driving distance at a specific tee off location on her local golf course. The golfer considered the following factors:
T = Tee height (cm)
H = Holes the golf ball had been played for prior to the experimental tee shot
C = Club type
D = Time of day (on the 24 hour clock)
The data are in standard order, however the actual experiments were run in random order.
Coded values for A, B, C, and D should be used in the linear
  regression model analysis, with -1 representing the low value and +1 the
  high value.
data(golf)A data.frame containing 16 observations of 4 variables (A, B, C, D, with y as a response variable.)