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# scikits.statsmodels.robust.norms.Hampel

class `scikits.statsmodels.robust.norms.``Hampel`(a=2.0, b=4.0, c=8.0)

  Hampel function for M-estimation.

  Parameters: | a : float, optional b : float, optional c : float, optional The tuning constants for Hampel’s function. The default values are a,b,c = 2, 4, 8.

  See also

  `scikits.statsmodels.robust.norms.RobustNorm`

  Methods

  `psi`(z) | The psi function for Hampel’s estimator
  `psi_deriv`(z) |
  `rho`(z) | The robust criterion function for Hampel’s estimator
  `weights`(z) | Hampel weighting function for the IRLS algorithm

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