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cash

gammapy.stats.cash(n_on, mu_on)[source]

Cash statistic, for Poisson data.

The Cash statistic is defined as:

\[C = 2 \left( \mu_{on} - n_{on} \log \mu_{on} \right)\]

and \(C = 0\) where \(\mu <= 0\). For more information see Fit statistics

Parameters:
n_on : array_like

Observed counts

mu_on : array_like

Expected counts
Returns:
stat : ndarray

Statistic per bin

References