Hi folks,

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? <crosses fingers>

Using Excel 97, Win XP.

tia,

LeAnne

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