DS.penalty {distance.sample.size} | R Documentation |
Calculates the variance penalty factor due to unknown detection parameters in conventional distance sampling.
DS.penalty(detection.function = c("halfnormal", "hazard"), theta, mean.detection.prob.value, w, P = 0, stop = F)
detection.function |
The detection function. Only "halfnormal" and "hazard" (hazard rate) are supported at present. |
theta |
The detection function parameters. A single value for halfnormal, or a vector of two values for hazard rate. |
mean.detection.prob.value |
An optional value specifying the mean detection probability over the range of observation. If this is supplied, the first element of theta should be set to NA, and theta[1] will be calculated using mean.detection.prob.value and detection.function. |
w |
The maximum range of observation. Objects at distance greater than w from the observer are assumed to never be recorded. |
P |
The proportion of the region of interest that is within w of an observer's path. P=0 may be assumed if the region is large relative to the observed area. |
stop |
Set to T to open a browser window (for debugging purposes) |
A single numeric value giving the asymptotic factor by which the variance is inflated due to unknown detection parameters.
Buckland S, Anderson D, Burnham K, Laake J and Borchers D (2001). Introduction to Distance Sampling: Estimating Abundance of Biological Populations. Oxford: Oxford University Press.
Clark, R. G. (2016), "Statistical efficiency in distance sampling," PLoS One, forthcoming, www.plosone.org
DS.penalty(detection.function="hazard",theta=c(NA,2),mean.detection.prob.value=0.6,w=1)