The examples below use Stata 8. If you are using Stata version 9, please see this page.
This example is taken from Lehtonen and Pahkinen’s Practical Methods for Design and Analysis of Complex Surveys.
This example provides the numbers necessary to use the formula in the middle of page 106. The svyreg is run to get the coefficient of hou85 and the svytotal is run to get the estimated total of hou85. These numbers are used in the formula and the result (15312) is shown in the last line of Table 3.14 on page 107.
input id str clu wt ue91 hou85 gwt adjwt smplrat 1 1 1 4 4123 26881 .5562 2.2248 .25 2 1 4 4 760 4896 .5562 2.2248 .25 3 1 5 4 721 3730 .5562 2.2248 .25 4 1 15 4 142 556 .5562 2.2248 .25 5 1 18 4 187 1463 .5562 2.2248 .25 6 1 26 4 331 1946 .5562 2.2248 .25 7 1 30 4 127 834 .5562 2.2248 .25 8 1 31 4 219 932 .5562 2.2248 .25 end gen fpc = 32 svyset [pweight=wt], fpc(fpc) psu(clu) svyreg ue91 hou85
Survey linear regression pweight: wt Number of obs = 8 Strata: <one> Number of strata = 1 PSU: clu Number of PSUs = 8 FPC: fpc Population size = 32 F( 1, 7) = 44949.18 Prob > F = 0.0000 R-squared = 0.9982 ------------------------------------------------------------------------------ ue91 | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- hou85 | .1520142 .000717 212.01 0.000 .1503188 .1537097 _cons | 42.65468 20.54033 2.08 0.076 -5.915492 91.22485 ------------------------------------------------------------------------------ Finite population correction (FPC) assumes simple random sampling without replacement of PSUs within each stratum with no subsampling within PSUs.
svytotal hou85 Survey total estimation pweight: wt Number of obs = 8 Strata: <one> Number of strata = 1 PSU: clu Number of PSUs = 8 FPC: fpc Population size = 32 ------------------------------------------------------------------------------ Total | Estimate Std. Err. [95% Conf. Interval] Deff ---------+-------------------------------------------------------------------- hou85 | 164952 87298.57 -41476.32 371380.3 1 ------------------------------------------------------------------------------ Finite population correction (FPC) assumes simple random sampling without replacement of PSUs within each stratum with no subsampling within PSUs. Weights must represent population totals for deff to be correct when using an FPC. Note: deft is invariant to the scale of weights.