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.

1 |

A data frame with 60 observations on the following 3 variables.

`Foot`

an ordered factor with levels

`1`

<`2`

<`3`

<`4`

`Lines`

an 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`

`count`

number 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.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | ```
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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