EXCEL tools:

In general you are advised not to use the built-in linear fitting function in EXCEL. However, for fitting to a straight line or polynomial, there are some EXCEL macros which properly account for errors in either the independent or dependent variable. These were written by Prof. Boyd for Physics 275. You can use them in this course.

To use these files, you need to enable Excel to run macros.

"LinFit.xls" performs a linear fit to the data. The fitted function is a straight line:

            y = a0 + a1*x

In the file, there are columns labeled x, sig-x, y, sig-y. Be sure to enter your data in the correct columns. Also enter the number of points you would like to fit. To run the macro, go to the Tools drop-down menu, click on Macros, then highlight the one called LINFIT, and click on RUN. The resultant fit will show up in the boxes to the right of the data. The errors obtained for the fit parameters are also displayed.  You will have to construct your own graphs.

"ParaFit.xls" performs a parabolic fit to the data. The fitted function is:

            y = a0 + a1*x  + a2*x^2