Gas Probability By this process, we can investigate the sensitivity of the probability distributions to individual parameters. In order to apply Bayes’ Theorem to (I,G) points from a real seismic data set, we need to “calibrate” the real data points. We define two scalers, S global and Sgradient, this way: Iscaled Gscaled This means that we need to determine a scaling from the real data amplitudes to the model amplitudes.