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Re: Air resistance

At 12:00 PM 12/10/97 -0400, Ludwik wrote:
I have no idea how averaging is done
inside of Mac Motion. Can somebody help us on this?

"15 point" averaging means that in finding the slope of the distance vs
time graph, a linear least-squares fit is done to 15 points centered on the
time value to be calculated. This means that the first 7 and last 7 points
of the data series are not calculated in the same manner, but have
truncated sets of fewer than 15 points. The word "averaging" is not used
very appropriately in MacMotion.

In Logger Pro (soon available on the Mac, and destined to replace
MacMotion) you have separate choices of the number of points used to
calculate derivatives (the fitting scheme mentioned above) and true
averaging, in which case a moving average is applied to a data column with
the goal of data smoothing. Calculating a derivative and averaging are thus
two distinct operations.

JEG


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John E. Gastineau gastineau@mindspring.com KC8IEW
900 B Ridgeway Ave. http://gastineau.home.mindspring.com
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