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
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...
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.
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...