sex. a factor with levels m w d, giving the proband's sex
age. a numeric vector
cms. a numeric vector
risk. a dichotome vector, 0 = not at risk, 1 = at risk
expert. a dichotome vector of expert's decision, 0 = not at risk, 1 = at risk
decu. a dichotome vector, 0 = no decubitus, 1 = decubitus