Excel can do this calculation for you. The Excel program is not a tutorial, however. It is best used by someone with some familiarity of statistics and data analysis. Use the "help" pull down menu and type in "Regression Analysis".
Your OP referred to MAX/MIN slope through some data points which I have never seen presented as a method to analyze data. I am familiar with least squares residual analysis as it relates to linear regression analysis. As a chemist, my suggestion would be to look at an undergraduate Analytical Chemistry text and refer to the chapter dealing with the evaluation of analytical data. My book is "Fundamentals of Analytical Chemistry", Chapter 3, by Skoog and West, 4th edition, Philadelphia: Saunders College Publishing (1982).
This type of data analysis is useful to most other branches of science such as Biology, Physics, Sociology, Public Health Administration, Political Science, etc... All of these disciplines have their own applications for this type of Statistical Analysis. A discussion of the underlying statistics of linear regression can be found at:
"Statistical Methods in Research and Production", 4th ed., O.L. Davies and P.L. Goldsmith, Eds., Chapter 7, New York: Hafner Publishing Co. (1972).
"Introduction to Statistical Analysis", W.J. Dixon and F.J. Massey, Jr., 3rd edition, New York: McGraw-Hill (1969).
You should be able to find newer editions of books titled "Introduction to Statistics (or Statistical Analysis)" at the bookstore or you might find these examples at your local University Library.
