Beta values of methylation data: mean or median? how to create an event?

Question

[deathmagnetic20]

I have filtered in R a Illumina Human Methylation 450K data into a data frame of my cg's of interest. Look like this:

 head(x_filtered[1:3])

               TCGA-WB-A81T-01A TCGA-WB-A81G-01A TCGA-WB-A815-01A
cg12150457       0.12335296       0.10067159       0.13113157
cg07035961       0.17139128       0.31152824       0.04598332
cg01089834       0.07643279       0.11007415       0.05539685
cg11429969       0.10935966       0.29668556       0.09419880
cg10649903       0.10081063       0.43367623       0.07381163
cg26282566       0.13038106       0.08354794       0.10883622

I would like to make the mean value (or median?) of each rowname and create an event dividing the data into up- and down- the median (1 for upregulated, for example).

I would appreciate suggestions, please.