Data are from Keith and Merrill (1983). `The effects of Vitamin C on
maximum grip strength and muscular endurance,' Journal of Sports Medicine
and Physical Fitness, 23:253-256.

Data are endurance measurements (number of repetitions) for 15 subjects.
Experiment was performed once after ingestion of 600mg ascorbic acid and
once after ingestion of a placebo (double-blind crossover design with two 
periods).  Order in which two treatments were given is also recorded.

These data were taken from the web site OzData at 

   http://www.maths.uq.edu.au/~gks/data/