st: Query: "Before-and-after" line graphs and the 'xtline' command

["David Fisher" <djfisher81@msn.com>]

Hi all,
I am working on a study where a group of women were measured before and 
after a month during which they were given a nutritional supplement 
intervention.  I would like to create a graph with a line for each subject 
(overlaid on the same plot), joining their "before" and "after" measurements 
for a particular variable (blood vitamin B12, say).  I can do this, roughly, 
by using the "tsset" and "xtline, overlay" commands.
What I am having trouble with, however, is controlling the look of these 
lines.  The nature of the "xtline, overlay" command seems to be that you 
have to alter each line individually using the "plopts#" option.  Using a 
local macro to create a huge line of text to alter each line one after the 
other doesn't work because would be "too many options".  Is there a way to 
change all the lines at once (specifically, I would like them to be all the 
same colour, or ideally one of 3 colours depending on their supplement 
category)?  E.g. can I say something like "plopts1/77()" (this doesn't work, 
by the way!)  Or, failing that, is there a completely different approach to 
the problem?
Thanks,
David Fisher.


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