How to set a filter for an estimated maximum price

Question

I cannot figure out how to set an estimated maximum price for a collection of records.

What I want to avoid is to simply use SQL MAX, because maybe there are records with exorbitant prices.

For example, in the "computers-hardware" category of OLX (http://www.olx.com/computers-hardware-cat-240) the filter for maximum price is estimately set to $1400, but sorting by price, the first items are above $10000

Maybe they calculated the average and then estimated some maximum price... what do you think?

Answer 1

so what is that you are asking for? computers do what they are exactly asked to do. Look into statistical functions - median etc. (http://en.wikipedia.org/wiki/Median)

Answer 2

If you assumed normal (gaussian) distribution on the prices you could estimate the maximum using this formula

avg(price) + 3*stddev(price)

If the distribiution is indeed gaussian about 95% of the samples should be contained within [avg - 3*stddev ; avg + 3*stddev]