Saturday, December 31, 2005
st: Outliers in correlation analysis
I have a very simple question.... I am trying to correlate two things using pearsons correlation, the results are non-significant due to one particular outlier (total number of observations = 36). If I exclude this outlier, there is a strong correlation between the other 35 patients (and this result makes biological sense)
I checked if there were any biological reasons why this outlier should be excluded, there are none.
These are cognitive tests, and it is possible that the outlier possibly was distracted and was not able to perform well.
How should I deal with the problem? Are there any defined criteria for dealing with outliers in correlational analysis and if possible, is there a reference I can quote?
Thanks, and a very happy new year, Siddharth.
* * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/
Links to this post: