Demonstrate the validity of the standard error formula (8.5). In the additive model assume that all covariates are centered (i.e., the mean values of all individuals at risk have been subtracted) at...

Demonstrate the validity of the standard error formula (8.5).

In the additive model

assume that all covariates are centered (i.e., the mean values of all individuals at risk have been subtracted) at all event times. Show that B0(t) is identical to the Nelson Aalen estimator.