I would like to have a rectanglar drawing object representing two standard
deviations shown and automatically move around a value on a normal curve. I
have plotted a second point in the graph referring to the IQ score and have
copied a shape to become the new custom marker for the point so that the
rectangle shows an area about 2 standard deviations around the IQ. However,
the custom marker hangs below the x-axis, whereas I would prefer that it not
hang down below the x-axis. I would like the rectangle to extend above the
x-axis however. Suggestions?

I have attached the file I'm working on as well. Any help would be
appreciated.