The mortality and drinking water hardness for 61 cities in England and Wales.
A data frame with 61 observations on the following 4 variables.
a factor with levels
whether the town is as north as Derby.
the name of the town.
averaged annual mortality per 100.000 male inhabitants.
calcium concentration (in parts per million).
The data were collected in an investigation of environmental causes of disease. They show the annual mortality per 100,000 for males, averaged over the years 1958-1964, and the calcium concentration (in parts per million) in the drinking water for 61 large towns in England and Wales. The higher the calcium concentration, the harder the water. Towns at least as far north as Derby are identified in the table. Here there are several questions that might be of interest including, are mortality and water hardness related, and do either or both variables differ between northern and southern towns?
D. J. Hand, F. Daly, A. D. Lunn, K. J. McConway and E. Ostrowski (1994). A Handbook of Small Datasets, Chapman and Hall/CRC, London.
data("water", package = "HSAUR") plot(mortality ~ hardness, data = water, col = as.numeric(water$location))