Hi Rick, I am happy I found your race results plot and histogram. I have plotted the same type of data in the same formats using excel. Rather than actual time I used gaps from the winner. I plotted 3 classes of boys and girls, athletes competing in the Minnesota State High School Cross Country Championship. All of the curves revealed the same shapes, but the slope of the large middle groups were slightly flatter in the more competitive “big school” races than the smalls. And, oddly, the most competitive race was the girls’ AA, as that group had the least dispersion and smallest SD. The ranking of the top 20 boys included kids from all 3 classes but the best times were all from AAA. Is there an equation that describe the results that you posted?