James,

> It happens frequently that we will sell one foal for $200,000 plus and the
> next one for $10,000.
>
> At what point do you categorize a single sale price as shewed and
> therefore a "special cause" or "out of control". Is there a formula to
> help determine this?
>

You may want to check how the census determine what is an outlier and what they do about them. I don't know if thee US Census Bureau publishes their methodology but I know that the Canadian equivalent did at some point (I moved to the States 5.5 years and I don't keep track of what's happening north of the border).

By the way, Peter uses the term 'outlier' which is the word you want to search for in these publications.

Just out of curiosity. Do you keep statistics about
Racing Event
Horse age at event (may be calculated if DOB is stored)
Number of furlongs
Track type (dirt, grass, etc.)
Track condition (fast, mnuddy, etc.)
Purse
Starting Position
Final Position
Winnings
for the mare, the sire, and the foals?

Daniel