Serious polling requires careful data collection and careful adjustment. It doesn't mean much to say your poll is a "probability sample" when your nonresponse rate is 90 percent.

In simple random sampling, each unit has an equal probability of selection, and sampling is without replacement. Without-replacement sampling means that a unit cannot be selected more than once.

One form of non-probability sampling is convenience sampling, meaning sampling based on accessibility and opportunity. For instance, we can draw our participants from patients at various hospitals.

Use of probability-based panels has become more prevalent. A growing number of pollsters have turned to sampling from a list of residential addresses from the U.S. Postal Service database to draw a ...

In a simple random sample, all combinations of population members are equally likely. The simple random sample is the ideal against which all other probability samples must be judged. Its strengths ...

We assume that the natural first-phase sample is collected with probability of selection proportional to size for each unit. The objective is then to use the ranked set sampling procedure to obtain a ...

Ashley L. Buchanan, Michael G. Hudgens, Stephen R. Cole, Katie R. Mollan, Paul E. Sax, Eric S. Daar, Adaora A. Adimora, Joseph J. Eron, Michael J. Mugavero, Generalizing evidence from randomized ...

Systematic sampling is low risk, controllable and easy, but this statistical sampling method could lead to sampling errors and data manipulation.