Options when drawing using the Curve Fitting tool

I am inputting x y z data and using 'Curve Fitting tool' to create a nonlinear regression graph.

I am trying to find the coefficients a,b,c,d suitable for the data using the 'Custom Equation' formula, but the graph is too different from the data.

I tried changing Robust and Algorithm, but the graph is not similar to the data.

What additional work should I do to get the graph?

I also attached a data file.

Answer 1

[Abdolkarim Mohammadi]

Your datapoints seem to have a polynomial relationship, not logarithmic. I think your should change your model. In addition, visual check is not enough for curve fitting. There are lots of things to check after fitting the model in order to reach a good model. Please read:

https://www.mathworks.com/help/curvefit/curve-fitting.html

Especially fit potsprocessing > residual analysis.