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 ...

Categorical Variable: the variable whose values can be put into categories (groups). Cluster Sampling: a researcher divides the population into clusters. Then, a simple random sample of the clusters ...

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 ...

In complex survey data, often the sampling design induces a non-iid structure to the data (e.g., without replacement sampling, stratification, multistage, or unequal probability of selection). Though ...

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 ...

Producers of infant formula employ comprehensive food safety systems, including product testing to ensure those systems are working. A new study from the University of Illinois Urbana-Champaign finds ...

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 based an evaluation of adaptive cluster sampling (Thompson, 1990, Journal of the American Statistical Association 85, 1050-1059) on a simulation experiment where samples were drawn from an ...