```
# NOT RUN {
dat <- infert[order(infert$stratum), ] # order by strata
post <- stan_clogit(case ~ spontaneous + induced + (1 | education),
strata = stratum,
data = dat,
subset = parity <= 2,
QR = TRUE,
chains = 2, iter = 500) # for speed only
nd <- dat[dat$parity > 2, c("case", "spontaneous", "induced", "education", "stratum")]
# next line would fail without case and stratum variables
pr <- posterior_linpred(post, newdata = nd, transform = TRUE) # transform=TRUE gives probabilities
# not a random variable b/c probabilities add to 1 within strata
all.equal(rep(sum(nd$case), nrow(pr)), rowSums(pr))
# }
```

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