A matched case control study carried out to investigate the connection between X-ray usage and acute myeloid leukemia in childhood. The pairs are matched by age, race and county of residence.
data(amlxray)A data frame with 238 observations on the following 11 variables.
IDa factor denoting the matched pairs
disease0=control, 1=case
SexF or M
downsPresence of Downs syndrome: no or yes
ageAge in years
MrayDid the mother ever have an Xray: no or yes
MupRayDid the mother have an Xray of the upper body
during pregnancy: no or yes
MlowRayDid the mother have an Xray of the lower body
during pregnancy: no or yes
FrayDid the father ever have an Xray: no or yes
CrayDid the child ever have an Xray: no or yes
CnRayTotal number of Xrays of the child 1=none
< 2=1 or 2 < 3=3 or 4 < 4= 5 or more