Function coverage_based_default 

pub fn coverage_based_default(n_hits: usize, n_total: usize, floor: f64) -> f64

Default probability for documents missing from a signal, interpolated by the signal’s coverage (Section 5, Paper 3 / Section 4, Paper 4):

default = 0.5 * (1 - r) + floor * r

where r = n_hits / n_total. A signal that returns nothing reports neutral evidence (0.5, logit 0); a signal that covers everything flags absence as strong negative evidence (= floor, default 0.01).