Wondering how many people in the United States have a smartphone? If you poll 20 people on the street, your survey won’t be representative of the entire American population. But if you just want to ...

Define statistical power List the potential consequences of doing a study that has low power, and also a study that has too much power. Explain what a type 1 and type ...

Determination of sample size is one of the critical decisions in forming a customer survey. Though you can find numerable statistical guides, and sample size calculators available, many people find ...

Jason Fernando is a professional investor and writer who enjoys tackling and communicating complex business and financial problems. Erika Rasure is globally-recognized as a leading consumer economics ...

If a tax impact study, derived from observations on income tax returns, is to provide tax estimates with the same margin of error and significance level for each ...

An explanation of the methodology for 538's current polling averages. 538 goes through many steps to calculate its polling averages. ABC News Photo Illustration This is an old version of our polling ...

Acknowledgments: I am grateful to Mary Mack, CEDS, CISSP, for her valuable feedback on an early draft of this piece. At some point eDiscovery practitioners seem to have tacitly agreed that sample ...