RMA

The RMA normalisation routine performs a quantile normalisation, [1]. This is a non-parametric procedure that works as follows:
  1. Compute the quantile of each value in the distribution of probe intensities.
  2. Transform the original value to that quantiles value on the reference chip:

    $\displaystyle \mathbf{x}_{\mathrm{norm}}=F_i^{-1}(F_{\mathrm{ref}}(\mathbf{x}),$    

    where $ F_i$ is the distribution function of chip $ i$, and $ F_{\mathrm{ref}}$ is the distribution function of the reference chip.
One strong assumption made in this procedure is that the distribution of probe intensities are identical.



Bjørn Kåre Alsberg 2006-04-06