Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.


dpb
Posts:
9,253
Registered:
6/7/07


Re: duplicate data points in scatterplot
Posted:
Nov 4, 2009 4:36 PM


ruud verschaeren wrote: ... > I have a scatter plot with some duplicate data points. The standard > code writes these on top of each other. In statistical programs they > have ways of showing this is a double or triple data point. In matlab > I haven't found these methods. Are there standard formulas or file > exchange scripts that do this? I had a look but found nothing. > > some examples: sunflowerplot and jitterplot: > http://www.ats.ucla.edu/stat/spss/faq/jitter.htm > > is there something around for Matlab? ... If file exchange didn't uncover it, perhaps not.
Doesn't look like the jitter solution would be too difficult to implement, however. Add a percentage factor onto each data point coordinate for each duplicate entryof course it ends up w/ the question in general of "what's a duplicate?" in floating point comparisons possibly as well as just how many duplicate points do you really want to be able actually discern?
Another solution I've seen (altho I don't have a handy example to link to) uses a circle or other figure and adjust its size so the area (or diameter) is proportional to the number of points.
Yet another would be to annotate the locations w/ the number of points textually.
But, to answer the original question, "I don't know"... :)




