The data on 30,000 races shows
pacers average class of 77.6 giving average time of 115.6 secs
trotters average class of 76.2 giving average time of 118.6 secs
(includes off tracks)
There is a problem in using TM class to section (bin) the groups because the number itself is a derivative of the racetime. So that brings us back to the old discussion of how to measure class.
There's also the effect of track size, track condition, DTV
I've got too many things going right now so I'll just post the numbers and let others do the work.
http://wikisend.com/download/752730/racetimes.csv
