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 ...

Last month, a “Questionnaire for Sheriffs and County Commissioners” was submitted to the Ravalli County Clerk. The unsigned cover sheet states that it was designed for officials to “affirm” that they ...

To select a sample with PROC SURVEYSELECT, you input a SAS data set that contains the sampling frame, or list of units from which the sample is to be selected. You also specify the selection method, ...