El. Korn et Bi. Graubard, EXAMPLES OF DIFFERING WEIGHTED AND UNWEIGHTED ESTIMATES FROM A SAMPLESURVEY, The American statistician, 49(3), 1995, pp. 291-295
Unweighted estimators using data collected in a sample survey can be b
adly biased, whereas weighted estimators are approximately unbiased fo
r population parameters. We present four examples using data from the
1988 National Maternal and Infant Health Survey to demonstrate that we
ighted and unweighted estimators can be quite different, and to show t
he underlying causes of such differences.