Consider the example in the section "Stratified Sampling". The study population is a junior high school with a total of 4,000 students in grades 7, 8, and 9. Researchers want to know how much these ...

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 ...

Samples are then chosen from each group. Stratified sampling is best used when a population is diverse. For example, if a company wanted to determine employee satisfaction, it would make no sense ...

Some drug developers are addressing this by incorporating tissue sample collection ... HER2 diagnostic test, an example that is widely considered to be a paradigm for stratified medicine.