| Although it would be good to get statistical gurus to comment on this I think it's a nigh on impossible prove.
People who dive Nitrox tend to do it when they have some experience so comparing a control group becomes virtually impossible. What Nitrox do you use in order to measure 22%, 23%, ...... 32% or 36% ? Shallow dives, deep dives, first dive of the day, last dive of the day, all dives etc etc etc so again it becomes more difficult to the point of impossible to measure, I think.
If I might paraphrase Mr. Pooley (and I am not sure if he was quoting someone else) ..... "I do not need to be hit on the head by a brick, to know I do not want to get hit on the head by a brick"
Mal |