The nickel
data frame has 679 rows and 7 columns.
The data concern a cohort of nickel smelting workers in South Wales and
are taken from Breslow and Day, Volume 2. For comparison purposes,
England and Wales mortality rates (per 1,000,000 per annum)
from lung cancer (ICDs 162 and 163),
nasal cancer (ICD 160), and all causes, by age group and calendar period, are
supplied in the dataset ewrates
.