Computes components of variance for average p=n/N and average p(0) with weights based on empirical covariate distribution, if it contains covariates.
Arguments
- model
- ddf model object 
- fct
- function of detection probabilities; currently only average (over covariates) detection probability p integrated over distance or average (over covariates) detection probability at distance 0; p(0) 
- vcov
- variance-covariance matrix of parameter estimates 
- observer
- 1,2,3 for primary, secondary, or duplicates for average p(0); passed to fct 
- fittedmodel
- full fitted ddf model when - trial.fior- io.fiis called from- trialor- iorespectively
Value
- var
- variance 
- partial
- partial derivatives of parameters with respect to fct 
- covar
- covariance of n and average p or p(0)