Sampling Methodology

Sampling is the selection of a subset of a population.

The goal of sampling is to obtain a representative sample of the population in order to form generalizations about the population from the sample data.

Probability sampling is the best way to achieve the goal, especially if you have access to the full population. If you don't have access to the full population, such as in a general population study, a non-probability sample of a known population can still provide direction needed to answer your questions.

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Sample Size Calculator

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Population Size: The total number of individuals in the population of interest. If unknown, enter 0.

Examples: the number of individuals on a subscription list; the number of individuals residing in a location; the number of attendees to a conference; the number of records in a database.

Margin of Error: Margin of Error or Confidence Interval: The amount of error tolerated from a random sample.

Margin of error is typically used in the footnotes in the media when reporting survey and poll results.

Confidence Level: The confidence level is the probability an estimate in a sample survey is also true for the population.