This example is taken from Levy and Lemeshow’s
Sampling of Populations.
page 167 stratified random sampling: allocation of sample to strata
This example uses the jacktwn data set.
proc descript data = jacktwn filetype = sas means totals design = strwor; nest stratum; weight sampwt; totcnt npop; setenv decwidth = 3; subgroup quart1; levels 3; tables quart1; var twin; run;
Number of observations read : 831 Weighted count : 256998 Denominator degrees of freedom : 813 Variance Estimation Method: Taylor Series (STRWOR) by: Variable, QUART1. ----------------------------------------------------------------------------------- | | | | Variable | | QUART1 | | | Total | 1 | 2 | ----------------------------------------------------------------------------------- | | | | | | | TWIN | Sample Size | 831.000 | 329.000 | 369.000 | | | Weighted Size | 256998.000 | 63937.000 | 127874.000 | | | Total | 26055.397 | 19183.803 | 6737.907 | | | SE Total | 3791.044 | 2661.629 | 2696.605 | | | Mean | 0.101 | 0.300 | 0.053 | | | SE Mean | 0.015 | 0.042 | 0.021 | ----------------------------------------------------------------------------------- Variance Estimation Method: Taylor Series (STRWOR) by: Variable, QUART1. ----------------------------------------------------- | | | | Variable | | QUART1 | | | 3 | ----------------------------------------------------- | | | | | TWIN | Sample Size | 133.000 | | | Weighted Size | 65187.000 | | | Total | 133.687 | | | SE Total | 126.744 | | | Mean | 0.002 | | | SE Mean | 0.002 | -----------------------------------------------------