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 ...

This is the description of the sample plan for a survey of enrollments by mail questionnaire of 1800 colleges and universities in the United States. The requirements of the survey included speed, ...

This work considers estimation of dichotomous characteristics of rare populations by sample survey. In particular, we investigate optimum allocation when a network sampling rule (also called ...

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 ...

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, ...