I've been hitting my head against the walls for a few days on this one. Hope you all can help:-)

I'm trying to create a sheet that allows anyone to enter in a set of data (columns for x and y) and then curvefit that data using the "linest" for a polynomial. The trick is that I would like to also allow the user to choose the order of the polynomial (3rd order, 4th order, etc.) from a drop down list and then I will take that equation back and graph the trendline on the same chart that has the data poitns plotted. I can't figure out how to make this variability happen. Please help.