background_error¶
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gammapy.stats.background_error(n_off, alpha)[source]¶ Estimate standard error on background in the on region from an off-region observation.
\[\Delta\mu_{bkg} = \alpha \times \sqrt{n_{off}}\]- Parameters
- n_offarray_like
Observed number of counts in the off region
- alphaarray_like
On / off region exposure ratio for background events
- Returns
- background
numpy.ndarray Background estimate for the on region
- background
Examples
>>> background_error(n_off=4, alpha=0.1) 0.2 >>> background_error(n_off=9, alpha=0.2) 0.6