What is a density plot?
The density plots (density vs log2 intensity (1/2(log2(cy5*cy3)))) are of single-channel log-intensity densities and illustrate the distribution of single-channel intensities. Normally the distribution of intensities should appear roughly bell-shaped; however depending on the choice of genes and the experiment conducted, the distribution of intensities may appear double-peaked or skewed to one side. Density plots can be useful for visually comparing different normalization methods. Density plots are produced using the R statistical language with the LIMMA package.