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 ...

Producers of infant formula employ comprehensive food safety systems, including product testing to ensure those systems are working. A new study finds that some testing methods are more powerful at ...

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, ...

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 consider semiparametric models for which solution of Horvitz-Thompson or inverse probability weighted (IPW) likelihood equations with two-phase stratified samples leads to $\sqrt N $ consistent and ...

The following PROC SURVEYSELECT statements select a probability sample of customers from the Customers data set according to the stratified sample design. title1 'Customer Satisfaction Survey'; title2 ...