Ratios.

Men run faster than women, both at 100m and at 26 miles (marathon distance). But is the gender gap any different at different distances? What would you guess?

Women's 100m world-record time/Men's 100m world-record time = 1.08256

Women's marathon world-record time/Men's marathon world-record time = 1.08827

That seems remarkably similar! Obviously, the sample size is as small as it can get, but the numbers are interesting.

Note: The two fastest 100m times by women are suspect. The first, 10.49 by Florence Griffith-Joyner in 1988, is often considered to have been wind-aided (with a malfunctioning wind meter at the event). The second, 10.65 by Marion Jones in 1998, was at altitude (more than 1000m above sea level). In addition, Flo-Jo was suspected of using performance-enhancing drugs, and Jones has admitted to it. The fastest time, then, that is considered completely legitimate is 10.73 seconds by Christine Arron of France, in 1998. The ratio of that time to Usain Bolt's (insane, but so far legitimate) 9.69 seconds is 1.10733 -- a larger difference than in the marathon.