ddf.trial.fi  R Documentation 
MarkRecapture Analysis of Trial Observer Configuration with Full Independence
## S3 method for class 'trial.fi'
ddf(
dsmodel = NULL,
mrmodel,
data,
method,
meta.data = list(),
control = list(),
call = ""
)
dsmodel 
not used 
mrmodel 
markrecapture model specification 
data 
analysis dataframe 
method 
analysis method; only needed if this function called from

meta.data 
list containing settings controlling data structure 
control 
list containing settings controlling model fitting 
call 
original function call used to call 
The markrecapture data derived from a trial observer distance sampling survey can be used to derive a conditional detection function (p_1(y)) for observer 1 based on trials (observations) from observer 2. It is a conditional detection function because detection probability for observer 1 is based on seeing or not seeing observations made by observer 2. Thus, p_1(y) is estimated by p_12(y). If detections by the observers are independent (full independence) then p_1(y)=p_12(y) for each distance y. In fitting the detection functions the likelihood given by eq 6.12 or 6.17 in Laake and Borchers (2004) is used. That analysis does not require the usual distance sampling assumption that perpendicular distances are uniformly distributed based on line placement that is random relative to animal distribution. However, that assumption is used in computing predicted detection probability which is averaged based on a uniform distribution (see eq 6.13 of Laake and Borchers 2004).
For a complete description of each of the calling arguments, see
ddf
. The argument model
in this function is the same
as mrmodel
in ddf
. The argument dataname
is the name
of the dataframe specified by the argument data
in ddf
. The
arguments control
,meta.data
,and method
are defined the
same as in ddf
.
result: a trial.fi model object
Jeff Laake
Laake, J.L. and D.L. Borchers. 2004. Methods for incomplete detection at distance zero. In: Advanced Distance Sampling, eds. S.T. Buckland, D.R.Anderson, K.P. Burnham, J.L. Laake, D.L. Borchers, and L. Thomas. Oxford University Press.
ddf.trial
, summary.trial.fi
,
coef.trial.fi
, plot.trial.fi
,
gof.trial.fi
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