| skulls | R Documentation |
Measurements made on Egyptian skulls from five epochs.
data("skulls")
A data frame with 150 observations on the following 5 variables.
epochthe epoch the skull as assigned to,
a factor with levels c4000BC c3300BC,
c1850BC, c200BC, and cAD150,
where the years are only given approximately, of
course.
mbmaximum breaths of the skull.
bhbasibregmatic heights of the skull.
blbasialiveolar length of the skull.
nhnasal heights of the skull.
The question is whether the measurements change over time. Non-constant measurements of the skulls over time would indicate interbreeding with immigrant populations.
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("skulls", package = "HSAUR2")
means <- tapply(1:nrow(skulls), skulls$epoch, function(i)
apply(skulls[i,colnames(skulls)[-1]], 2, mean))
means <- matrix(unlist(means), nrow = length(means), byrow = TRUE)
colnames(means) <- colnames(skulls)[-1]
rownames(means) <- levels(skulls$epoch)
pairs(means,
panel = function(x, y) {
text(x, y, levels(skulls$epoch))
})
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