The ambitious goal of identifying signs of life via biosignature gases in an exoplanet atmosphere is within reach. The James Webb Space Telescope has a chance to be the first to provide evidence of biosignature gases. But how high is this chance? We need to first discover a pool of super Earths transiting in the "extended" habitable zones of nearby, quiet M stars. Life must not only exist on one of those planets, but the life must produce biosignature gases that are spectroscopically active. Exoplanets with H2-rich atmospheres are the most accessible for transmission spectroscopy due to their inflated scale height. To estimate the probability for biosignature gas detection we can use both quantitative and speculative terms in a "revised Drake equation" . And when its inputs are allowed to be random variables, rather than just sheer numbers, this "revised statistical Drake equation" leads to a lognormal distribution for the probability of biosignature gas detection. Explicit equations yielding this lognormal were recently derived, highly enhancing the computer simulations of expected biosignatures.