Modeling spatial relationships

[CanZhang]

Hello everyone,

Q1:

I’m reading the page of “Modeling spatial relationships” in ArcGIS Help 10.1.  In the section “Selecting a fixed-distance band value”,  there is one sentence: “The z-scores are reliable (even with skewed data) as long as the distance band is large enough to ensure several neighbors (approximately eight) for each feature.”

Does anyone know, what’s the mathematical basis of “eight neighbors”? Why are eight neighbors normally enough for a reliable z-score?

Q2:

Is there a tool in ArcGIS, with that I can calculate an average radius for every point, when they have, for example, eight neighbors?

Thank you all!

[KishorGhatage]

Thanks a lot Jenora.