| Dactyl | R Documentation |
Edgeworth (1885) took the first 75 lines in Book XI of Virgil's Aeneid and classified each of the first four "feet" of the line as a dactyl (one long syllable followed by two short ones) or not.
Grouping the lines in blocks of five gave a 4 x 25 table of counts,
represented here as a data frame with ordered factors, Foot and
Lines. Edgeworth used this table in what was among the first
examples of analysis of variance applied to a two-way
classification.
data(Dactyl)
A data frame with 60 observations on the following 3 variables.
Footan ordered factor with levels 1 < 2 < 3 < 4
Linesan ordered factor with levels 1:5 < 6:10 < 11:15 < 16:20 < 21:25 < 26:30 < 31:35 < 36:40 < 41:45 < 46:50 < 51:55 < 56:60 < 61:65 < 66:70 < 71:75
countnumber of dactyls
Stigler, S. (1999) Statistics on the Table Cambridge, MA: Harvard University Press, table 5.1.
Edgeworth, F. Y. (1885). On methods of ascertaining variations in the rate of births, deaths and marriages. Journal of the [Royal] Statistical Society, 48, 628-649.
data(Dactyl)
# display the basic table
xtabs(count ~ Foot+Lines, data=Dactyl)
# simple two-way anova
anova(dact.lm <- lm(count ~ Foot+Lines, data=Dactyl))
# plot the lm-quartet
op <- par(mfrow=c(2,2))
plot(dact.lm)
par(op)
# show table as a simple mosaicplot
mosaicplot(xtabs(count ~ Foot+Lines, data=Dactyl), shade=TRUE)
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