summary.dfunc: Summarize a distance function object

Description

A summary method for distance functions produced by dfuncEstim, which are of class dfunc.

Usage

# S3 method for dfunc
summary(object, criterion = "AICc", ...)

Value

The input distance function object (object) is invisibly returned with additional components:

convMessage: The convergence message. If the distance function is smoothed, the convergence message is NULL.
effDistance: The ESW or EDR.
pDetect: Probability of detection in the strip.
AIC: AICc, AIC, or BIC of the fit, which ever was requested.
coefficients: If the distance function has coefficients, the coefficient matrix with standard errors, Z values, and p values. If the distance function is smoothed, it has no coefficients and this component is NULL.

Arguments

object: An estimated distance function resulting from a call to dfuncEstim.
criterion: A string specifying the criterion to print. Must be one of "AICc" (the default), "AIC", or "BIC". See AIC.dfunc for formulas.
...: Included for compatibility with other print methods. Ignored here.

Details

The call, coefficients of the distanced function, whether the estimation converged, and the likelihood form are printed. The following quantities are then printed,

Strip : The left (w.lo) and right (w.hi) truncation values.
Effective strip width or detection radius : ESW or EDR as computed by effectiveDistance.
Probability of Detection : Probability of detecting a single target in the strip.
Scaling : The horizontal and vertical coordinates used to scale the distance function. Usually, the horizontal coordinate is 0 and the vertical coordinate is 1 (i.e., g(0) = 1).
Log likelihood : Value of the maximized log likelihood.
Criterion : Value of the specified fit criterion (AIC, AICc, or BIC).

The number of digits printed is controlled by options()$digits.

Examples

Run this code

# Load example sparrow data (line transect survey type)
data(sparrowDetectionData)

# Fit half-normal detection function
dfunc <- dfuncEstim(formula=dist~1,
                    detectionData=sparrowDetectionData)

# Print results
summary(dfunc)
summary(dfunc, criterion="BIC")