nbinom2() defines a one-response count distribution with formulas for the
mean mu and overdispersion scale sigma.
Value
A drm_family object.
Details
The implemented contract is
log(mu) = eta_mu, log(sigma) = eta_sigma, and
Var(y) = mu + sigma^2 * mu^2. Thus larger sigma means greater
extra-Poisson variation. Internally this is equivalent to the usual NB2
size parameter size = 1 / sigma^2.
Examples
nbinom2()
#> $name
#> [1] "nbinom2"
#>
#> $family
#> [1] "nbinom2"
#>
#> $n_response
#> [1] 1
#>
#> $dpars
#> [1] "mu" "sigma"
#>
#> $links
#> mu sigma
#> "log" "log"
#>
#> attr(,"class")
#> [1] "drm_family"
