This is the Dysphagia data
These are the columns and their meanings
out
Outcome: a factor with values 1 to 4, indicating the outcome
Chemo
Whether the patient underwent chemotherapy ("ja" is yes, "nee" is no)
SNP_XRCC1__77
Genotype of this SNP. A factor with three levels: "TT", "TC" and "CC"
SPC_D2
Dose of radiation that reached 2
SNP_XRCC1__77TC
1 if SNP_XRCC1__77
is "TC", 0 otherwise