plot_regression() interpretation

[maialenzaze]

Hi everyone,

I'm having difficulty interpreting what the visual components of the Visually Weighted Regression plot mean.

From what I read, the dark grey lines must be smoothed bootstrapping lines, which are followed by lighter blue near the center regression. I interpret that blue shadow to be the probability of the dependent variable (y) to belong to the corresponding independent variable (x) point. This is shown in the Scaled Density in the legend. Does the central color or the line being white mean that the scaled density is 1?

So what is the "Alpha Factor" in the legend then? And where is it visually showing in the plots? Is it corresponding to smoothed bootstrapping lines and their interposing?

Thank you everyone,

I attach a plot I made with this function as an example.
random.pdf