Package

r-vsn

Description

Variance stabilization and calibration for microarray data. The package
implements a method for normalising microarray intensities, and works
for single- and multiple-color arrays. It can also be used for data from
other technologies, as long as they have similar format. The method uses
a robust variant of the maximum-likelihood estimator for an additive-
multiplicative error model and affine calibration. The model
incorporates data calibration step (a.k.a. normalization), a model for
the dependence of the variance on the mean intensity and a variance
stabilizing data transformation. Differences between transformed
intensities are analogous to "normalized log-ratios". However, in
contrast to the latter, their variance is independent of the mean, and
they are usually more sensitive and specific in detecting differential
transcription.

Note