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On the face of it, that's absolutely insane.

Idk, hard to guess based on the layman description, but maybe what they are describing is a rolling average? That would be quite a standard low-pass filter for applications like this.

Hard to get upset over that. What matters is not the signal processing but the validation. You take a bunch of people with various blood alcohol levels measured by some already accepted lab technique and you verify that your new measurement technique is measuring within some acceptable error bound of that.

That’s not the formula for a rolling average though

It is the formula for an exponentially weighted moving average.

Which is not appropriate here...

An exponential moving average is a form of weighted rolling average that would match the plain-text description in the complaint and is often used in signal processing as an IIR low-pass filter (an unweighted rolling average over a window is an FIR filter)

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