Extended Data Fig. 5: The probability density function (PDF) (left) and the cumulative distribution function (CDF) (right) of the 105 simulated maximum Δχ2 values.
From: Evidence for a compact object in the aftermath of the extragalactic transient AT2018cow

The vertical dashed red line marks the value of the Δχ2 of the observed 224 Hz QPO. The false alarm probability (1-CDF) vs Δχ2 is shown in the right panel of Fig. 1. The false alarm probability of seeing a spurious signal as strong as the one seen in data at 224 Hz is 0.0002 (1 in 5000).