Narrow Range Day

[tradertom]

I am trying to develope a "narrow range day" scan. To determine if today is a NRD I want to look at the previous 24 days. Throw out the 2 highest days and the two lowest days. From the 20 days left I will take the average of the range (H-L)/20. I want my NRD to be less than the average of this 20 day range. How do I write this scan so that the 2 highest and 2 lowest days are excluded from the average range?

Thanks,
Tradertom