Picture, if you will, an Excel graph with 2 bell-curves plotted on
it...one curve shows the freqency distribution of measurement values at
"good," or reference, sites, and the other shows the distribution of
values at "bad," or impaired, sites. At some point on the graph the
curves intersect (hopefully at the inflection points, assuming a
more-or-less normal distribution for both populations of sites). The
"curves" are actually XY scatterplots with smoothed lines and no
markers, using data sorted into uniform "bins" generated by Tools | Data
Analysis | Histogram. Now, I can add vertical lines to the graph to
show the median (50th %ile) of each distribution using the technique at
Kelly O'Day's website
(http://processtrends.com/pg_charts_vertical_line.htm), because I "know"
(i.e. can calculate) the median value for each pop. But what I would
*really* like to do is add a vertical line to the chart at the
intersection point for these 2 curves. I have 21 of these charts (7
measures, 3 biological regions) and prefer not to have to eyeball all
those intersection points, then hard-code in the values for each graph
to make the intersection line. Is this even possible? Or let me phrase
it another way...is it possible without VB?
Using Excel 97, Win XP.