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 ...

Histograms are a way of representing data. They are like bar charts, but show frequency density instead of the frequency. They can be used to determine the distribution of data. Module 4 (M4) - ...

It is shown that variance estimates for regression coefficients in exposure-stratified case-cohort studies (Borgan et al 9 Lifetime Data Anal., 6,2000,39-58) can easily be obtained from influence ...

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 ...