A survey that used a simple one-stage cluster sampling design was conducted in a large city in China. The clusters in this instance were entities known as

"neighborhood groups" (translated from the Chinese "jumin xiaozu"), which are essentially groups of contiguous households. These so-called neighborhood groups are the smallest units for which population information is available in the Peoples Republic of China (PRC). The city comprises six districts that, in this design, comprise the strata. Within each district, a simple random sample of two neighborhood groups was selected, and all individuals within each neighborhood group were interviewed concerning their overall health status. The following table represents data from the survey on the number of individuals over 30 years of age who were edentulous.

Strata 1, 2, 4, and 6 each contain 200 neighborhood groups; stratum 3 contains 175 neighborhood groups; and stratum 5 contains 150 neighborhood groups. Estimate and construct 95% confidence intervals for (1) the total number of edentulous persons 30 years of age and over, and (2) the proportion of all persons 30 years of age and older who are edentulous.