iact_estimator.statistics

Functions that implement some statistical formulas.

Functions

sigma_to_probability(sigma)	Convert significance to one side of the two-sided probability.
probability_to_sigma(probability)	Inversion function of .sigma_to_probability().
significance_li_ma(n_on, n_off, alpha[, mu_sig])	Get the Li & Ma significance.

Module Contents

iact_estimator.statistics.sigma_to_probability(sigma)

Convert significance to one side of the two-sided probability.

Parameters:

sigmafloat

Significance value.

Returns:

probabilityfloat

Probability value.

iact_estimator.statistics.probability_to_sigma(probability)

Inversion function of .sigma_to_probability().

Parameters:

probabilityfloat

Probability value.

Returns:

sigmafloat

Significance value.

iact_estimator.statistics.significance_li_ma(n_on, n_off, alpha, mu_sig=None)

Get the Li & Ma significance.

This is equivalent to eq.17 of [1].

Parameters:

n_onint

Measured counts in ON region.

n_offint

Measured counts in OFF region.

alphafloat

Acceptance ratio of ON and OFF measurements.

mu_sigfloat

Expected signal counts in ON region.

Returns:

sqrt_tsfloat`

Significance as the square root of the Test Statistic.

Notes

The implementation uses gammapy.stats.WStatCountsStatistic and takes the square root of the Test Statistic.

References

[1]

Li, T.-P. & Ma, Y.-Q., ApJ, 1983, 272, 317, 10.1086/161295.