COUNT (version 1.3.4)

ships: ships

Description

Data set used in McCullagh & Nelder (1989), Hardin & Hilbe (2003), and other sources. The data contains values on the number of reported accidents for ships belonging to a company over a given time period. When a ship was constructed is also recorded.

Usage

data(ships)

Format

A data frame with 40 observations on the following 7 variables.

accident

number of shipping accidents

op

1=ship operated 1975-1979;0=1965-74

co.65.69

ship was in construction 1965-1969 (1/0)

co.70.74

ship was in construction 1970-1974 (1/0)

co.75.79

ship was in construction 1975-1979 (1/0)

service

months in service

ship

ship identification : 1-5

Details

ships is saved as a data frame. Count models use accident as the response variable, with log(service) as the offset. ship can be used as a panel identifier.

References

Hilbe, Joseph M (2007, 2011), Negative Binomial Regression, Cambridge University Press Hilbe, Joseph M (2009), Logistic Regression Models, Chapman & Hall/CRC Hardin, JW and JM Hilbe (2001, 2007), Generalized Linear Models and Extensions, Stata Press McCullagh, P.A, and J. Nelder (1989), Generalized Linear Models, Chapman & Hall

Examples

data(ships)
glmshp <- glm(accident ~ op + co.70.74 + co.75.79 + offset(log(service)),
              family=poisson, data=ships)
summary(glmshp)
exp(coef(glmshp))
library(MASS)
glmshnb <- glm.nb(accident ~ op + co.70.74 + co.75.79 + offset(log(service)),
                   data=ships)
summary(glmshnb)
exp(coef(glmshnb))
if (FALSE) {
library(gee)
shipgee <- gee(accident ~ op + co.70.74 + co.75.79 + offset(log(service)),
              data=ships, family=poisson, corstr="exchangeable", id=ship)
summary(shipgee)
}