To your co-worker: next generation sequencing technologies have bias, too. Everything and everyone has bias.

You posted the question here, too: [removed on July 2, 2020 as malware detected at URL]

Look, mmmmm, go HERE, click on the R script tab, and then you will be presented with code that allows you to retrieve the normalised values.

The data that is available is normalised beta values:

library(Biobase)
library(GEOquery)

# load series and platform data from GEO
gset <- getGEO("GSE145254", GSEMatrix =TRUE, getGPL=FALSE)
if (length(gset) > 1) idx <- grep("GPL23976", attr(gset, "names")) else idx <- 1
gset <- gset[[idx]]

boxplot(exprs(gset))