In
survey methodology
Survey methodology is "the study of survey methods".
As a field of applied statistics concentrating on human-research surveys, survey methodology studies the sampling of individual units from a population and associated techniques of survey d ...
, Poisson sampling (sometimes denoted as ''PO sampling''
) is a
sampling process where each element of the
population
Population is a set of humans or other organisms in a given region or area. Governments conduct a census to quantify the resident population size within a given jurisdiction. The term is also applied to non-human animals, microorganisms, and pl ...
is subjected to an
independent Bernoulli trial
In the theory of probability and statistics, a Bernoulli trial (or binomial trial) is a random experiment with exactly two possible outcomes, "success" and "failure", in which the probability of success is the same every time the experiment is ...
which determines whether the element becomes part of the sample.
[Ghosh, Dhiren, and Andrew Vogt. "Sampling methods related to Bernoulli and Poisson Sampling." Proceedings of the Joint Statistical Meetings. American Statistical Association Alexandria, VA, 2002]
(pdf)
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Each element of the population may have a different probability of being included in the sample (). The probability of being included in a sample during the drawing of a single sample is denoted as the ''first-order inclusion probability
In statistics, in the theory relating to sampling from finite populations, the sampling probability (also known as inclusion probability) of an element or member of the population, is its probability of becoming part of the sample during the dra ...
'' of that element (). If all first-order inclusion probabilities are equal, Poisson sampling becomes equivalent to Bernoulli sampling In the theory of finite population sampling, Bernoulli sampling is a sampling process where each element of the statistical population, population is subjected to an statistical independence, independent Bernoulli trial which determines whether the ...
, which can therefore be considered to be a special case of Poisson sampling.
A mathematical consequence of Poisson sampling
Mathematically, the first-order inclusion probability
In statistics, in the theory relating to sampling from finite populations, the sampling probability (also known as inclusion probability) of an element or member of the population, is its probability of becoming part of the sample during the dra ...
of the ''i''th element of the population is denoted by the symbol and the second-order inclusion probability that a pair consisting of the ''i''th and ''j''th element of the population that is sampled is included in a sample during the drawing of a single sample is denoted by .
The following relation is valid during Poisson sampling when :
:
is defined to be .
See also
*Bernoulli sampling In the theory of finite population sampling, Bernoulli sampling is a sampling process where each element of the statistical population, population is subjected to an statistical independence, independent Bernoulli trial which determines whether the ...
*Poisson distribution
In probability theory and statistics, the Poisson distribution () is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time if these events occur with a known const ...
*Poisson process
In probability theory, statistics and related fields, a Poisson point process (also known as: Poisson random measure, Poisson random point field and Poisson point field) is a type of mathematical object that consists of Point (geometry), points ...
*Sampling design In the theory of finite population sampling, a sampling design specifies for every possible sample its probability of being drawn.
Mathematical formulation
Mathematically, a sampling design is denoted by the function P(S) which gives the probabi ...
References
Sampling techniques
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