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Parzen window

The Parzen window method is a way of estimating the probability density function of a random variable. As an illustration, given some data about a sample of a population, the Parzen window method makes it possible to extrapolate the data to the entire population.

If x1, x2, ..., xN is a sample of a random variable, then the Parzen window approximation of its probability density function is

\rho(x)=\frac{1}{N}\sum_{i=1}^N W(x-x_i)

where W is some kernel. Quite often W is taken to be a Gaussian function with mean zero and variance σ2:

W(x) = {1 \over \sigma\sqrt{2\pi} }\,e^{-{x^2 / 2\sigma^2}}.

See also

References

  • Parzen E. (1962). On estimation of a probability density function and mode, Ann. Math. Stat. 33, pp. 1065-1076.
  • Duda, R. and Hart, P. (1973). Pattern Classification and Scene Analysis. John Wiley & Sons. ISBN 0471223611.

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01-04-2007 01:18:14
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