Recent content by liquidFuzz

I think i understand the subject well enough to implement it in code (which I usually do when I thinker). One question though. To calculate the variance of the function value I take the Jacobian J of the function and the Covariance matrix C of the curve fit and multiply as such v = J C J T...

Hm. i might have been vague in my post, sry... We could use the growth model example, but I fear it might be to complicated, for me... I have four detector signals Sxx where my output = (Saa - Sab)(Sba - Sbb). The detector is the same so all signals have the same uncertainty. If understand this...

I would like to find a measurement for uncertainty in a calculation I have. So, the uncertainties I have, or at least as far as I understand. uncertainty of sampled data that is used to optimized parameters of the model. uncertainty in the curve fit procedure Is there some fairly...

Hi thanks for chipping in! I have a fully functional implementation of the model i wrote, its commonly known as the 5PL model. I was curious to know more about its origin.

Hi, I'm wondering how the asymmetric logistic growth model is derived. My main interest is this version that I've implemented in python. $$ growth(t) = d + \frac{a - d}{(1 + (x/c)^b)^g} $$ In particular, how is the asymmetry variable introduced? Best, Fuzz

Thanks! I'll play around with merged bins and see if I get something useful out of it. I was hoping for a clear yes or no... 🤪

A question regarding zero entries in expected values. Lets say I want to test whether a set of data could be considered normal distributed. How do I treat bins where the expected value is close to zero. Fewer bins or just upright rejecting the hypothesis..? Edit, additional, if I instead tests...

Thanks!

What are my observed values yi and expected value ei if you calculated a model with a least square method?

I have a curve fit of a nonlinear function (a growth model). As a sanity check I do a chi2 test, but I'm not really sure how to set it up properly. My data is as such: sample point and estimated points. In a chi2 test the variables are often referred to as observations and expected. What would...

True! I have transferred the shape into a CAD program and I had to calculate (approximated) Bézier splines to keep the nodes at a reasonable level. I think I ended up with 12 nodes or so to get a smooth contour that was fairly similar to the shape I was going for. The continuation of this is...

I tried your excel-file and it crashes as soon as I edit length, width, and string length. :-/ My don't crash so I stick with the analytical solution for now. I think I'll just go with brute force for the corners, when I have some spare time.

How big is e, in your approximation? Cool! I also hold a masters degree in physics. :-)

BVU, I have read all your posts. Stating "I'm not sure I follow you" was me trying to be polite about the fact that your approximation is not so good. :angel: The shape is ellipsoid in appearance but it is not an ellipsoid. So, as stated before. I have an analytical expression for the sides...

I'm not sure I follow your calculations BVU. Is it what I'm looking for..? I attached the excel I tried the calculations in. There you can see the segments I still haven't got, the corners. Oh, I should mention that I used Libreoffice for this tinkering. Edit, these spread sheets are a bit...