[R] Question about normalization to a set of internal standards
Frank E Harrell Jr
f.harrell at vanderbilt.edu
Mon Mar 2 03:48:08 CET 2009
> I have a question of the method as how to normalize the data sets
> according to a set of the internal measurements.
> For example, I have performed two batches of experiments contrasting
> two different conditions (positive versus negative conditions): one at
> a time.
> 1. each experiment, I measure signals of variable v1 to v100. I want
> to understand v1 to v100 change under these two contrasting conditions
> 2. Also I know different variables v101 to v1110, total of 10 of them,
> although they are different from each other, but they would of the
> same or similar values under these two contrasting conditions
> 3. How do I do the internal normalization? How can I use the the
> variable v101 to v110 values to normalize the measures of v1 to v100
> at either positive or negative condition to minimize batch effect? I
> hope the comparisons of values (v1 to v100) between two different
> conditions can be more accurate and robust to external noises.
> In general, I have a couple of matrices of the same dimensions and a
> reference matrix of values to be used as reference values to be
> normalize to. How should I do that?
I don't understand your problem well, but in general internal
normalization is by and large an attempt to avoid appropriate modeling
(e.g., incorporating block effects or certain covariates in a regression
model), and results in overstated confidence of the final estimates by
not taking into account the imprecision in the normalizing factors.
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University
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