Hello All, I want to improve myself in data fitting in order to derive new equations for the data from experimental results and/or performance analysis. I am an engineering researcher and since I found some out-of-world formulations derived from performance data, I need to learn this advanced data fitting (or whatever its name is) discipline. Please guide me to the exact field name and/or books to achieve this skill. I guess that this is not just Math but also Physics so that one could put the relationship between the input data and/or dimensionless quantities. For example: How come one could derive this formulation for the correction factor data (LMTD heat exchanger) as shown below: Here is the formulation/expression: For the graph: Thank you in advance.