I am currently reading a paper of Bolstad "A comparison of normalization nethods for high density oligonucleotide array data based on variance and bias: and I have some questions about the result-section.

He writes:

Plotting the log of the ratio of variances versus the average of the log of the mean (expression measure across arrays)..

for example:

"the log of the ratio of variances" is then log[ Variance(Quantil) / Variance(unnormalized) ]

"the average of the log of the mean" is then 0.5* [log (Mean(Quantil) * Mean(unnormalized) ]

Is it right? Because a few lines later he mentions: *...the first method ib the ratio has the smaller ratio...*

has the smaller ration of what? reatio of variance(Qunatil) and mean(Quantil)? but we did not compare that.