The SURVEYREG Procedure

Sampling Rate of the Pooled Stratum from Collapse

Assuming that PROC SURVEYREG collapses single-unit strata $h_1, h_2, \ldots , h_ c$ into the pooled stratum, the procedure calculates the sampling rate for the pooled stratum as

\[  f_{\mbox{Pooled Stratum}}= \left\{  {\begin{array}{ll} 0 &  \mbox{if any of } f_{h_ l}=0 \mbox{ where } l=1, 2, \ldots , c \\ {\displaystyle \left( \sum _{l=1}^ c n_{h_ l}f_{h_ l}^{-1} \right)^{-1} \sum _{l=1}^ c n_{h_ l}} &  \mbox{otherwise} \end{array} } \right.  \]