VGAMdata (version 1.1-13)

birds.df: A Bird Data Set

Description

An undocumented data set concerning birds.

Usage

data("birds.df")

Format

A data frame with 67 observations on the following 15 variables.

Species

a character vector

Status

a numeric vector

Length

a numeric vector

Mass

a numeric vector

Range

a numeric vector

Migr

a numeric vector

Insect

a numeric vector

Diet

a numeric vector

Clutch

a numeric vector

Broods

a numeric vector

Wood

a numeric vector

Upland

a numeric vector

Water

a numeric vector

Release

a numeric vector

Indiv

a numeric vector

Details

This is a data set used in a book (or in a draft version of a book). Unfortunately very few details seem available concerning the background and the variables. The purpose of its inclusion in VGAMdata is to show that a logistic regression applied to these data, mimicking the book, has estimates suffering from the Hauck--Donner effect (HDE; hdeff). It is called model.final in the book.

Examples

data(birds.df)
str(birds.df)

model.final.copy <-   # Try mimic the book example
  vglm(Status ~ Upland + Migr + Mass + Indiv + Insect + Wood,
       binomialff, data = birds.df, trace = TRUE)
summary(model.final.copy, hde.NA = FALSE)  # Wald table
hdeff(model.final.copy)
hdeff(model.final.copy, deriv = 2)