What I'm trying to do is ... I have a frequency graph, with frequencies on the y axis, and student grades on the x a xis.
the student grades are ...
The graph is a stacked column chart, where I'm using circles to represent the columns, so if 6 students achieved a B+, then instead of a single rectangular bar positioned above the B+ stretching up to a frequency of 6, I have 6 small circles.
I would like to have a solid black circle sitting at the top of a given stack of circles, so if cell D2 says B+, and cell E2 says 6, then at the intersection of B+ and 6 I would like a solid black circle, to contrast with the other circles, which are a black rim and filled with white inside.
Could the graph have a coordinate overlay coinciding with the 15 categories running along the x axis, and the 30 numbers running up the frequency axis (the y axis).