Learn how representative samples and random samples differ and why combining them minimizes sampling bias for accurate data.

Suppose that the sample of students described in the previous section was actually selected using stratified random sampling. In stratified sampling, the study population is divided into ...

We consider semiparametric models for which solution of Horvitz-Thompson or inverse probability weighted (IPW) likelihood equations with two-phase stratified samples leads to $\sqrt N $ consistent and ...

It’s a truism that even large samples can be misleading if they are biased or, as market and social researchers say, if they are not representative for the universe. Therefore, it is essential whether ...

Suppose that the previous student sample is actually drawn from a stratified sampling. The strata are grades in the junior high school: the 7th grade, the 8th grade, and the 9th grade. Within strata, ...