do proportional hazards give valid predicted probabilities? can proportional hazards be used for hazard prediction what is survivor function in a proportional hazards model why does a survivor's function need to be based on a proportional hazards model? can you use proportional hazards for survival and hazard is survivor function valid do proportional hazards estimates give valid predicted probabilities of an event happening after a number of time periods? is a survivor function valid in proportional hazards? which is a valid survivor function? what is the survivor function in proportional hazards do proportional hazards models include hazard functions does proportional hazards model give valid predicted probabilities? which function of a survivor is invalid? why is it necessary? why is the survivor function valid when can an estimate a survivor function be used does a proportional hazards model give the survivor function do proportional hazards models include hazard is a survival function valid is a survivor model based on a proportional hazards model how accurate are proportional hazards