Estimation of infant mortality rates categorized by social class for an Australian population

"This paper reports a method of deriving simultaneous confidence intervals for [Australian] infant mortality rates based on a birth sample rather than the birth population. The large sample size employed enables the use of asymptotic multivariate techniques....[The authors find that] where the population distribution of a characteristic such as social class is not known, confidence intervals can be estimated for rates based on the distribution of this characteristic in a sample of that population."