On Sun, Nov 22, 2020 at 5:50 PM Ken Renard <kdrenard2@gmail.com> wrote:
On Nov 22, 2020, at 2:31 PM, Steve Crocker <steve@shinkuro.com> wrote:
Ken,
What is the justification for the numbers, e.g. 20 times, σ = .65, etc
The justification for σ = 0.65 is in the user narrative document, but pasted here:
desired probability 0.95 success rate for measurement point among N=3 RSIs. (1-p)^N = (1 - 0.95) p = 0.63. (for N=3) round to p = 0.65 note that desired rate of 0.95 is starting point for discussion
Ok, so this looks like you're trying to achieve a 95% probability of reaching an RSI using three attempts. Implicit in your model is the failures will be independent, an assumption worth discussing. And your math says if the probability of reaching an RSI is 65% or better, three (independent) attempts gives you a 95% probability of success because the probability of three failures is .35^3 ≅ .043, which is less than .05. What do you mean by "normalization?"
As for the “20" values, those are somewhat out of the blue. Just waiting for someone to ask why and start the discussion. For availability, we need a moderate number of samples. 20 samples seems reasonable to me right now, but open to other thoughts. As for averaging 20 metrics before competing to other sites, I just wanted something that can wash away some anomalies and get a better idea of what is happening at a location. I feel the same about the T=30 minute interval; open to ideas.
Thanks, Steve