Hello: I have been trying to find some information on choosing the width of a running average over a time dependent data set. Here is an example of what I am dealing with: The oscillations should be around the line y=15.6385 and I am wondering if there is a way to quantitatively detect gradual change in a oscillating system. If I do a linear fit of this data I get a line with a positive slope so I get the feeling that there is a gradual change. Any help would be nice. Thank you.