A fungus was grown in each of 15 culture dishes under three values of the 
pH for the medium in which they were grown (5 plates at each pH). Growth 
(measured as the diameter of the culture in the dish) was measured at days 
7, 11, 17, 21, 29, and 37.  The diameter was measured twice each time, at 
right angles.  The order of the data are pH, first diameter on day 7, 
second diameter on day 7, first diameter on day 11, second diameter on day 
11, etc.

Data source: Hand and Crowder (1996). Practical Longitudinal Data
Analysis. London: Chapman and Hall. (Table B2)