```
survreg(Surv(time, status) ~ temperature + voltage, capacitor)
# Replacement of valve seats. In this case the cumulative hazard is the
# natural target, an estimate of the number of replacements by a given time
# (known as the cumulative mean function = CMF in relability).
# When two valve seats failed at the same inspection, we need to jitter one
# of the times, to avoid a (time1, time2) interval of length 0
ties <- which(with(valveSeat, diff(id)==0 & diff(time)==0)) #first of a tie
temp <- valveSeat$time
temp[ties] <- temp[ties] - .1 # jittered time
vdata <- valveSeat
vdata$time1 <- ifelse(!duplicated(vdata$id), 0, c(0, temp[-length(temp)]))
vdata$time2 <- temp
fit2 <- survfit(Surv(time1, time2, status) ~1, vdata, id=id)
if (FALSE) {
plot(fit2, cumhaz= TRUE, xscale= 365.25,
xlab="Years in service", ylab = "Expected number of repairs")
}
```

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