CASE STUDIES IN BIOMETRY: Chapter 12. Parametric Duration Analysis of Nursing Home Usage Carl N. Morris, Edward C. Norton, Xiao H. Zhou The file ch12.dat contains the following variables: lstay: Length of stay of a resident age: Age of a resident trt: Nursing home assignment (1: receive treatment,0: control) gender: Gender (1:male,0:female) marstat: Marital status (1: married,0: not married) hlstat: Health status (2: second best, 5: worst) cens: Censoring indicator (1:censored, 0: discharged)