F.double.obs.prob | R Documentation |
Estimates the probability of detection in a two-observer system when observations are independent.
F.double.obs.prob(df, observer = "both")
df |
A data frame containing the components |
observer |
A number of text string indicating the primary observer. Primary observers can be
observer 1, or observer 2, or "both".
If, for example, observer 2 was a data recorder and part-time observer, or if observer 2
was the pilot, set |
When observer
= "both", the observers are assumed to be independent. In this case the estimate
of detection is
p = p_1 + p_2 - p_1p_2
where p_1
is the proportion of targets seen by observer 2 that were also seen by observer 1,
p_2
is the proportion of targets seen by observer 1 that were also seen by observer 2.
This estimator is very close to unbiased when observers are actually independent.
A single scalar, the probability of detection estimate.
dfuncEstim
, abundEstim
# Fake observers
set.seed(538392)
obsrv <- data.frame( obsby.1=rbinom(100,1,.75), obsby.2=rbinom(100,1,.5) )
F.double.obs.prob( obsrv, observer=1 )
F.double.obs.prob( obsrv, observer=2 )
F.double.obs.prob( obsrv, observer="both" )
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