How do I highlight an individual chart guideline in EXCEL?

[Guest]

I am attempting to highlight a single threshold gridline in an Excel chart.
I am able to highlight all of the chart gridlines, but not just the one I
want. I have MS Office XP. Any suggestions?

 

[Kelly O'Day]

Why not just add horizontal line to your chart?

Andy Pope has a tutorial on adding an average line to a line chart:
http://www.andypope.info/charts/averageline.htm

I have a tutorial on adding horizontal lines to an XY chart:
http://processtrends.com/pg_charts_horizontal_line.htm

(e-mail address removed)