Set the "Vary" check box for a particular parameter if you want it varied during the fit; otherwise leave it unchecked. (Notice that "Area" type parameters cannot be varied as they are not truly independent--they are calculated from the amlitude and the width). In general, it works best to start off by varying only one or two parameters, and then allow more parameters to vary in each subsequent fit, rather than allowing all of them to vary in the first attempt. |