I'm trying to create a dartboard chart using tableau (an example is attached - see image attached "dartboard_finalproduct_forum.png"). I tried using the background image function in Tableau where you can overlay an image on an x/y axis and plot data points. However, my data is a little bit different than what you would find in a standard scatterplot. For the dartboard that I'm trying to create, each user is plotted on the graphic based on a "score" they received (ranging from 1 - 10) with or without an intervention. The more answers they got right (of 10 questions), the higher the score. I need one dartboard graphic to show the before (what the users scored without the intervention) and one dartboard graphic to show the after (what the users scored with the intervention). The higher the score (i.e. the more answers the users got correct), the closer they would be to the center of the dartboard. The less they got correct, the farther away they would be from the center (if you look at the graphic png file this should make more sense).
I can get the data points to closer or farther away from the center based on the users individual scores, but I can't make the points scatter randomly around the circle (while still also showcasing how well the users did). I think applying some kinda of trig functions may do the trick, but that is beyond my math knowledge on how to do that. Currently, I am assigning random data points to what would be the y-axis variable in Excel and then using that file as my data source (please see attached Excel file for data source). The Tableau workbook that I have thus far is also attached. You'll see in my workbook that the data points do not surround the entire dartboard circle area and the way that I'm plotting the points doesn't show much of an improvement before and after (see the dashboard tab for comparison). Again, ideally I'm trying to create what is show in the png file attached. This graphic was created in Photoshop and is not based on any data calculations; someone created it as an example.