Cross-sectional Data from the New Zealand Population
A cross-sectional data set of a workforce company, plus another health survey, in New Zealand during the 1990s,
The data frame is a subset of the entire data set which was collected from a confidential self-administered questionnaire administered in a large New Zealand workforce observational study conducted during 1992--3. The data were augmented by a second study consisting of retirees. The data can be considered a reasonable representation of the white male New Zealand population in the early 1990s. There were physical, lifestyle and psychological variables that were measured. The psychological variables were headed "Questions about your feelings".
Although some data cleaning was performed and logic checks conducted, anomalies remain. Some variables, of course, are subject to a lot of measurement error and bias. It is conceivable that some participants had poor reading skills!
Clinical Trials Research Unit, University of Auckland, New Zealand,
More variables may be added in the future and these
may be placed in any column position. Therefore
references such as
xs.nz[, 12] are dangerous.
MacMahon, S., Norton, R., Jackson, R., Mackie, M. J., Cheng, A., Vander Hoorn, S., Milne, A., McCulloch, A. (1995) Fletcher Challenge-University of Auckland Heart & Health Study: design and baseline findings. New Zealand Medical Journal, 108, 499--502.
data(xs.nz) summary(xs.nz) # Handling of factors requires care is.factor(xs.nz$babies) # TRUE summary(xs.nz$babies) # Note the "-"s charbabies <- as.character(xs.nz$babies) summary(as.numeric(charbabies)) # "-"s converted to NAs + warning table(as.numeric(charbabies)) # Ditto