why hazard ratios are undefined what would a hazard ratio be if it were undefined can a hazard ratio be undefined how can hazard ratios be undefined how can hazard ratio can hazard ratios be undefined can hazard ratios be undefined? can you use undefined hazard ratios can hazard ratio be undefined? which is true about the undefined hazards ratio? why would a hazard ratio be undefined can undefined hazard ratios be considered higher or lower why is hazard ratio undefined can hazard ratios be undefined what is the difference between hazard ratio and undefined why is hazard ratio undefined? can undefined hazards ratio be used for the same variable? are hazards ratios undefined when a hazard ratio is undefined can a hazard ratio be undefined