How does 'statsCircularMeans' work?

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I have a group of circular means from which I wish to calculate the grand mean. Statscircularmeans seems perfect for this from the description, but the only reference to how it works is behind a paywall that I can't access. Is there any information anywhere else about how exactly it goes about its purpose?

Thanks!
I'm not familiar with the command so can't help. However, what's written in IgorMan.pdf looks pretty extensive (V-619 in v.6.4). The reference is to Zar's Biostatistical Analysis, it's a book but it might be worth using your favourite search engine to see if somebody has put it online as a PDF (I didn't say that).

February 7, 2015 at 11:30 am - Permalink

jamesbutler01 wrote:
I have a group of circular means from which I wish to calculate the grand mean. Statscircularmeans seems perfect for this from the description, but the only reference to how it works is behind a paywall that I can't access. Is there any information anywhere else about how exactly it goes about its purpose?

You can search online for second-order circular statistics. If you are doing any statistics getting a copy of Zar is actually a good idea.

Now for the details:

If you have a set of radii {Ri} and a set of angles {Ai} you can compute the rectangular grand means Xe and Ye as the averages of the respective components:

Xe=Sum{Ri*cos(Ai)}/N
Ye=Sum{Ri*sin(Ai)}/N

From this Re=sqrt(Xe^2+Ye^2)

and Ae=Atan2(Ye,Xe)

etc.

HTH,

A.G.
WaveMetrics, Inc.

February 9, 2015 at 10:21 am - Permalink