CASE STUDIES IN BIOMETRY: Chapter 21. Drug Interactions Between Morphine and Marijuana Chris Gennings, W. Hans Carter Jr., Billy R. Martin. The file ch21b.dat contains the tail-flick data. (510 observations of 6 variables) Missing data are encoded with a period. Variable List: OBS: Observation identification number. REP: Identification of study. Two 5x7 factorial experiments and one 5x5 factorial experiment are included. MORPHINE: Dose of morphine sulfate (mg/kg) injected into study mice. The range is 0 to 8.0. DEL9_THC: Dose of Delta9-THC (mg/kg) injected into study mice. The range is from 0 to 15.0. FLICK_C: Control Flick Time. The number of seconds required for the mouse to flick it tail from beneath a heat stimulus prior to treatment. FLICK_T:: Test Flick Time. The number of seconds required for the mouse to flick it tail from beneath a heat stimulus post treatment. A 10 sec maximum latency was imposed.