vcd (version 1.4-13)

Trucks: Truck Accidents Data

Description

Data from a study in England in two periods from November 1969 to October 1971 and November 1971 to October 1973. A new compulsory safety measure for trucks was introduced in October 1971. Therefore, the question is whether the safety measure had an effect on the number of accidents and on the point of collision on the truck.

Usage

data("Trucks")

Format

A data frame with 24 observations on 5 variables.

Freq

frequency of accidents involving trucks.

period

factor indicating time period (before, after) 1971-11-01.

collision

factor indicating whether the collision was in the back or forward (including the front and the sides) of the truck (back, forward).

parked

factor indicating whether the truck was parked (yes, no).

light

factor indicating light conditions: day light (daylight), night on an illuminated road (night, illuminate), night on a dark road (night, dark).

References

E. B. Andersen (1991), The Statistical Analysis of Categorical Data. 2nd edition. Springer-Verlag, Berlin.

Examples

library(MASS)
data("Trucks")
tab <- xtabs(Freq ~ period + collision + light + parked, data = Trucks)
loglm(~ (collision + period) * parked * light, data = tab)
doubledecker(collision ~ parked + light + period, data = tab)
cotabplot(tab, panel = cotab_coindep)