wstat#

gammapy.stats.wstat(n_on, n_off, alpha, mu_sig, mu_bkg=None, extra_terms=True)[source]#

W statistic, for Poisson data with Poisson background.

For a definition of WStat see WStat : Poisson data with background measurement. If mu_bkg is not provided it will be calculated according to the profile likelihood formula.

Parameters
n_onarray_like

Total observed counts.

n_offarray_like

Total observed background counts.

alphaarray_like

Exposure ratio between on and off region.

mu_sigarray_like

Signal expected counts.

mu_bkgarray_like, optional

Background expected counts.

extra_termsbool, optional

Add model independent terms to convert stat into goodness-of-fit parameter. Default is True.

Returns
statndarray

Statistic per bin.

References