Reproduce a best-fit 4-parameter sigmoid

Hi, I'm trying to reproduce this type of graph, which apparently represents the best-fit 4-parameter sigmoid, but I have no idea where to start.

I have KSS data (hourly values) and melanopic EDI data (also hourly values). Any idea how to do this? Thank you!

Answer 1

[the cyclist]

It is difficult when you say you have no idea. But, here are a few thoughts.

If you have never used MATLAB at all, then you have some work ahead of you in order to learn to fit a complicated equation using MATLAB. One good starting point is the MATLAB Onramp.

If you understand the basics of MATLAB, but just don't know how to plot your data, then I would suggest looking at the plot or scatter functions, or possibly

The most difficult part to code will likely be the model fitting. For this problem it looks like the fitnlm function from the Statistics and Machine Learning Toolbox would be appropriate.