How hard is this? I'd like to fit a cos^2 to some data for an experiment I'm doing, where the fit parameter will be the phase (i.e. d in y = cos^2 (x - d)). I'll have points with error, so a weighted ...

Fitting data with nonlinear regression -- Fitting data with linear regression -- Models -- How nonlinear regression works -- Confidence intervals of the parameters -- Comparing models -- How does a ...

Simply collecting data is not enough. You can fill spreadsheets with data, but it's useless if you can't act on it. Regression is one of the most powerful statistical tools for finding relationships ...