(08-25-2018 07:17 AM)ijabbott Wrote: The HP Prime (like its predecessors) supports user-defined regression functions although that might not be as useful as it sounds as the function cannot have any unknown coefficients.

As far as I was able to determine, that's just there to let you graph an arbitrary function along with your stat plot. It's sort of a side effect of splitting function graphing and stats into two separate "apps". Casio's approach is to let you press the "DefG" soft key while viewing a stat plot and also configure/draw function graphs. TI avoids this entirely by having a single "Graph" button that displays all defined function graphs and stat plots at once.