Statistics and other damn lies

I have (or rather SBAA has) accumulated about a decade of local race data. Almost 80,000 entries giving a runner’s time in a race. About 38,000 entries were run by men and about 40,000 by women.

I think it is interesting that in the under 19s there are more boys than girls, but the age-group 19-29 has more than half again as many women than men (12,800 women and 8,100 men). There continue to be more women than men until about 40, and after that the men start predominating. In the 65-69 there are three times as many men as women, and in 75-79 there are six time as many men.

Number of runners at various ages. Horizontal axis in years, vertical is a count of runners. Men in blue, women in red. There are more women runners who are 27 than any other age. There are more men runners who are 42. Combining both sexes the number of runners peak at age 26.

Is this the effect of Title IX that came out in ’72? Presumably it took a while for attitudes to change, but it might explain this discrepancy… Or do young women really like to run while older women hate it? Or does Santa Barbara have a very odd sex ratio with lots of young women and few older ones?

I also wondered what distances people preferred. From the graph below it’s clear that more people run 5Ks than anything else. Of course there are more 5K races than any other kind so it’s not clear which is cause and which effect. And we’ve only had a marathon for two years (as opposed to ~10 for the other races) so it shows to an unfair disadvantage, if you multiply it by 5 it would be a little below the number of half marathoners.

Interesting that more men than women seem to like miles, but more women like half marathons.

I’ve noticed that I tend to run 10Ks at a slightly higher age-graded percentage than I do any other race distance. I wondered if this were chance, unique to me, or a general trend… So I graphed that too:

I did not include races that are excessively downhill, those that are mostly uphill, nor those that I know to have been mismeasured. I also did not include the Night Moves course because I think it is more difficult than it should be. I wanted “fair” races.

Unfortunately the State St. Mile is the only mile race I’ve got data for, and it gets ruled out. Pity. I would like to see how well people run miles.

But it does look as though people are much more likely to do well on 10K races than at other distances. I’m actually rather surprised by that (even though I knew I did), I would have guessed that the shorter the race, the easier it would be to approach the world record…


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