[BioC] cDNA microarray Questions

Naomi Altman naomi at stat.psu.edu
Sat Feb 28 06:19:34 MET 2004


What do you mean by "very low"?

--Naomi

At 04:24 AM 2/27/2004, michael watson (IAH-C) wrote:
> >The correlation coefficients are very low. Is that the normal case?
> >Do I need to delete some poor quality genes before any analysis and
> >what rule should I use?
>
>Which correlation coefficient are you using?  I regularly see very low 
>pearson correlation coefficients between biological replicates but that 
>can be put down to natural biological variation - no two organisms are the 
>same, right?  BUT if you start seeing low correlations between technical 
>replicates (e.g. replicate samples from the same 
>animal/tissue/organ/whatever) then that indicates that you have a lot of 
>variation in your technology, which is bad.
>
>ON another note, I always find the Spearman Rank Correlation Coefficients 
>to be much higher.
>
>Mick
>
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Naomi S. Altman                                814-865-3791 (voice)
Associate Professor
Bioinformatics Consulting Center
Dept. of Statistics                              814-863-7114 (fax)
Penn State University                         814-865-1348 (Statistics)
University Park, PA 16802-2111



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