This is the first of a series of articles that will describe the different types of study design; considerations when choosing a study design; and the advantages and disadvantages of each type of ...

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 ...

Pew Research Center designed this study to assess the current state of online survey sampling methods – both probability-based and opt-in – and determine their accuracy on general population estimates ...

By Courtney Kennedy, Andrew Mercer, Scott Keeter, Nick Hatley, Kyley McGeeney and Alejandra Gimenez As the costs and nonresponse rates of traditional, probability-based surveys seem to grow each year, ...

Environmental Health Perspectives, Vol. 102, Supplement 8: Biostatistics in the Study of Human Cancer (Nov., 1994), pp. 47-51 (5 pages) A stratified version of nested case-control sampling which we ...