Stratified sampling is used to select a sample that is representative of different groups. If the groups are of different sizes, the number of items selected from each group will be proportional to ...

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 ...

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, ...

The authors advocate the use of the generalized variance of the sample means-the determinant of the variance-covariance matrix $D(\overline{y})$ of the means-as a ...

Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...

"Samples of five different cold drinks — Sprite, Mountain Dew, 7UP, Pepsi and Coca Cola — were selected by the stratified sampling method and the samples were submitted to National Test House (in ...