>> > You've entered a road race.  It's around a loop, a lakeside
> > > race, but very long, like a marathon.

> > > It contains a large field of competitors, including Median
> > > Mel, who's the median speed runner.  And Al Average,
> > > who runs at the average speed of the entire field.

> > > After a while, you get bored, so you start to count the
> > > runners whom you pass, and the runners whom pass
> > > you.  You notice something funny:  the number who pass
> > > you equals the number you pass, on average, per hour.
> > > How fast are you, relative to Al or Mel?

> > Regardless of the distribution of runner's speeds only the
> > averagespeed runner will, on average, be passed by the same
> > number of runners as he passes himself.
> > It's easy to prove this in a spreadsheet.

> Is there a hidden assumption somewhere that the speed of each
> runner is constant?

> You can get in trouble pretty quickly if half of the field is running at a
> constant speed and the other half is oscillating at a fixed period so that
> they are running faster and slower than you.