Both of these kinds of hazard rates obviously have divergent integrals. the hazard rate will typically (when the underlying process is reversible, i.e., can move back and forth) converge to a constant value. I A decreasing hazard rate would suggest "infant mortality". One such function is called the “force of mortality“, or “hazard (rate) function“. When deriving the hazard ratio, the hazard rate (death rate) for either treatment group may not be constant throughout follow-up (a is false). The Cox proportional hazards regression model can be written as follows: where h(t) is the expected hazard at time t, h 0 (t) is the baseline hazard and represents the hazard when all of the predictors (or independent variables) X 1 , X 2 , X p are equal to zero. However, it is assumed that the ratio of the death rates is constant across the study period and is the same, if only approximately, for each time interval. • The hazard rate is a more precise “fingerprint” of a distribution than the cumulative distribution function, the survival function, or density (for example, unlike the density, its tail need not converge to zero; the tail can increase, decrease, converge to some constant The failure rate is the rate at which the population survivors at any given instant are "falling over the cliff" The failure rate is defined for non repairable populations as the (instantaneous) rate of failure for the survivors to time \(t\) during the next instant of time. An alternative characterization of the distribution of Tis given by the hazard function, or instantaneous rate of occurrence of the event, de ned as (t) = lim dt!0 Prft T