Dataset:  ozonespruce.dat

Source: P.W. Lucas, D.A. Cottam, L.J. Sheppard, B.J. Francis (1988). "Growth
Responses and Delayed Winter Hardening in Sitka Spruce Following Summer
Exposure to Ozone," New Phytologist, Vol. 108, pp. 495-504.

Description: Damage scores (ordinal 0-4) for Picea Sitchesis shoots
at 2 Dates (10November and 8December), at 4 temperatures (different at
each date) and 4 ozone Levels

Variables/Columns
Date    8
Temp 13-16     /* Celsius  */
03 Concentration    20-24   /* nl/l  */ 
Damage Score   32
Count       38-40