Description Format Details References Examples

Counts of numbers of an insect, *Leptinotarsa decemlineata* (the
Colorado potato beetle), each of which is the sum for two plots treated
alike, for all combinations of 4 treatments and 6 areas of the field chosen
to be relatively homogeneous.

a 4 x 6 matrix, where the rows are treatments and the columns are areas of a field.

These data are used in Tukey (1977) Exhibit 1 of Ch 11 and throughout the chapter as examples of median polish. Because the data are counts, either a sqrt or log transformation would be reasonable.

Tukey, J. W. (1977). *Exploratory Data Analysis*, Reading MA: Addison-Wesley. Exhibit 1 of chapter 111

1 2 3 4 5 6 7 8 9 10 11 12 | ```
insect.2way <- twoway(insectCounts, method="median")
print(insect.2way, digits=2)
plot(insect.2way)
plot(insect.2way, which="diagnose")
# try sqrt transformation
insect.sqrt <- twoway(sqrt(insectCounts), method="median")
print(insect.sqrt, digits=2)
plot(insect.sqrt)
plot(insect.sqrt, which="diagnose")
``` |

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