Jarmo

Now there's a good question. At any given point on the time scale, provided you express
the value in arithmetic ohms and not in log10 ohms, I would say the arithmetic mean and
variance or SD. However, I believe that this is relatively meaningless unless you wish
to plot the whole time x R curve with SD limits, because the curve is probably noisy.
If you wish a mean end-value, I think you should average all the readings over the last
several hours. Better still, use exponential curve-fitting techniques on all the plots
over the total time and average plus SD each of the parameters and plot a new curve
from this: this would be the best statistical method, requiring a little
number-crunching using a good mathematical software (don't try it in a spreadsheet
application: you'll come to a very sticky end, it's a promise!).

Brian

Kiiski Jarmo wrote:

> To estimate the average of SIR-test results should arithmetic or geometric
> mean used and how standard deviation should calculated?
>
> B.R.
> Jarmo Kiiski
>
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