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 ...

We collaborate with the world's leading lawyers to deliver news tailored for you. Sign Up for any (or all) of our 25+ Newsletters. Some states have laws and ethical rules regarding solicitation and ...

It is shown that variance estimates for regression coefficients in exposure-stratified case-cohort studies (Borgan et al 9 Lifetime Data Anal., 6,2000,39-58) can easily be obtained from influence ...

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 ...