[R] correlating between two vectors of numbers
sdavis2 at mail.nih.gov
Thu Oct 14 14:53:24 CEST 2004
Does your data have missing values? It looks like they might. Look
at the 'use' parameter in cor. Also, is there a reason to use cor.test
instead of cor. Finally, if the expression values are not normal,
could you transform them first to make them more so--log2, for example?
And, no, no one has figured out the "best" way to define
distances/correlations for microarray, at least to the best of my
On Oct 14, 2004, at 8:37 AM, Anders Stegmann wrote:
> Hi, R!
> I am trying to correlate two vectors of numbers (two columns of
> signal values) by using the non-parametric Spearman's rank correlation
> coefficient rho:
> but I get the error message:
> Error in if (q > (n^3 - n)/6) pspearman(q - 1, n, lower.tail = FALSE)
> pspearman(q, :
> missing value where logical needed
> In addition: Warning message:
> NAs introduced by coercion
> I have tried to use the parametric Pearson correlation and the
> non-parametric Kendall's tau correlation and had no problem with that!!
> Pearson correlation)
> Kendall's correlation)
> what's wrong?
> Does anyone accidently know which correlation method would be the most
> correct to use when the microarray signal values (the values to be
> correlated) are not normal distributed (the Kendall's method seem to
> better to my other tests than the Pearson method).
> R-help at stat.math.ethz.ch mailing list
> PLEASE do read the posting guide!
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