diff options
Diffstat (limited to 'man/gpcount.Rd')
| -rw-r--r-- | man/gpcount.Rd | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/man/gpcount.Rd b/man/gpcount.Rd index f847baa..b7e3b1a 100644 --- a/man/gpcount.Rd +++ b/man/gpcount.Rd @@ -10,7 +10,7 @@ population size, availability, and detection probability. } \usage{ gpcount(lambdaformula, phiformula, pformula, data, -mixture = c("P", "NB"), K, starts, method = "BFGS", se = TRUE, +mixture = c("P", "NB", "ZIP"), K, starts, method = "BFGS", se = TRUE, engine = c("C", "R"), threads=1, ...) } \arguments{ @@ -27,7 +27,8 @@ engine = c("C", "R"), threads=1, ...) An object of class unmarkedFrameGPC } \item{mixture}{ - Either "P" or "NB" for Poisson and negative binomial distributions + Either "P", "NB", or "ZIP" for Poisson, negative binomial, or + zero-inflated Poisson distributions } \item{K}{ The maximum possible value of M, the super-population size. @@ -58,11 +59,13 @@ engine = c("C", "R"), threads=1, ...) \details{ The latent transect-level super-population abundance distribution \eqn{f(M | \mathbf{\theta})}{f(M | theta)} can be set as either a - Poisson or a negative binomial random variable, depending on the + Poisson, negative binomial, or zero-inflated Poisson random variable, depending on the setting of the \code{mixture} argument. The expected value of \eqn{M_i} is \eqn{\lambda_i}{lambda_i}. If \eqn{M_i \sim NB}{M_i ~ NB}, then an additional parameter, \eqn{\alpha}{alpha}, describes - dispersion (lower \eqn{\alpha}{alpha} implies higher variance). + dispersion (lower \eqn{\alpha}{alpha} implies higher variance). If + \eqn{M_i \sim ZIP}{M_i ~ ZIP}, then an additional zero-inflation parameter + \eqn{\psi}{psi} is estimated. The number of individuals available for detection at time j is a modeled as binomial: |