Little explorations with HP calculators (no Prime)

04032017, 03:03 PM
Post: #108




RE: Little explorations with the HP calculators
(04032017 08:52 AM)pier4r Wrote: While I still do not know how you got the fitting formula, I understood that you did not try to correlate the 1st and 3rd column of this matrix, but the 1st and the 2nd. You are correct, and I hadn't noticed until now that I was using the wrong column! All due to a single digit typo in a regex expression I used to clean up the table (I didn't want to retype all the values). I'm glad you took the time to doublecheck. Hopefully my mistake didn't cause too much confusion. My method of fitting the curve was far less scientific than may be appropriate, which is why I was concerned about its efficacy. In a nutshell, it was:  Used Excel to plot the data, observed that it was (roughly) a power curve reflected horizontally  Taking left side as first range, asked Excel to show the power trendline formula  Tweaked the formula slightly to more closely align the value at 3825 (to bring it closer to 425)  "Reflected" new xvalues (7250x), then plotted right half  Repeated the trendlinetweak for that range, with the same focus on the value at (new) xvalue 3425 to realign the peak (04032017 08:52 AM)pier4r Wrote: That would be even better actually, then I have the underlying X and I can extrapolate the "variance modifier" as I want. Then perhaps my mistake was a "happy accident". At the least, it showed the performance increase of the overall process when replacing the table lookup with a computation. Glad you caught the mixup when you did! 

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