lizards.RdAn entirely artificially constructed data set and context designed for classroom discussion and analysis.
The fictional context is that 384 different lizards have been observed in nature, from each of 4 different species ("A", "B", "C", or "D"). In addition to their species, the sex of each lizard was identified. At the time of observation, each lizard was perched on the branch of a bush. The perch height from the ground in feet was measured and the diameter in inches of the branch where the lizard was perched was measured. Lizards are collected and numbered (row.names) in the order they appear in the data set.
We could imagine the study having proceeded as follows.
Problem:
Suppose that we are interested in the habitat of lizards on some other remote island archipelago. Here there are trees of all heights and many different species of lizards. Interest lies in understanding the perch height preference for all lizards.
Plan:
As with the source study, lizards will be observed during daylight hours for two separate summer time expeditions. The height (in feet) at which the lizard is observed will be recorded as is the diameter (in inches) of the branch where the lizard is perched. The species and sex of each lizard will be recorded.
Data: A total of 384 lizards of several species were captured and measured together with the height and diameter of their perch when first spotted.
NOTE: The data are inspired by the reference but are otherwise entirely fictional and constructed primarily for pedagogical purposes. Instructors might choose to invent their own context.
A data frame with 384 rows and 4 variates
The height in feet where the lizard was found to be perched.
The diameter in inches of the branch where the lizard was perched.
The sex of the lizard: a factor with levels "male" and "female"
The species of lizard: a factor with four levels "A", "B", "C", and "D".
`rownames(lizards)` labels the order in which the lizards were collected.
T.W. Schoener (1968) “The Anolis lizards of Bimini: Resource partitioning in a complex fauna”, Ecology, Vol. 49, pp. 704-726.
R.W. Oldford