Zero-inflated binomial for the numerator when modeling proportions with excess zeros (e.g., species detection/non-detection).
$$P(Y = 0) = \pi + (1 - \pi) \cdot (1-p)^n$$ $$P(Y = y) = (1 - \pi) \cdot \binom{n}{y} p^y (1-p)^{n-y}, \quad y > 0$$
Details
Use this family when modeling proportions (successes/trials) where excess zeros occur beyond what binomial predicts. Common applications:
Species occupancy with false negatives
Survey data with non-response
Epidemiological data with under-reporting
Examples
# Create family object
fam <- ratiod_zibinomial()
print(fam)
#> tulpaRatio family: zibinomial
#> [Zero-inflated model]
#> Zero-inflated binomial numerator, fixed trials denominator
#>
#> Numerator: binomial(logit)
#> ZI prob: bernoulli(logit)
#> Denominator: fixed (fixed)