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lizards {bnlearn} R Documentation

Lizards' perching behaviour data set

Description

Real-world data set about the perching behaviour of two species of lizards in the South Bimini island, from Shoener (1968).

Usage

data(lizards)

Format

The lizards data set contains the following variables:

  • Species (the species of the lizard): a two-level factor with levels Sagrei and Distichus.
  • Height (perch height): a two-level factor with levels high (greater than 4.75 feet) and low (lesser or equal to 4.75 feet).
  • Diameter (perch diameter): a two-level factor with levels narrow (greater than 4 inches) and wide (lesser or equal to 4 inches).

Source

Edwards DI (2000). Introduction to Graphical Modelling. Springer, 2nd edition.

Fienberg SE (1980). The Analysis of Cross-Classified Categorical Data. Springer, 2nd edition.

Schoener TW (1968). "The Anolis Lizards of Bimini: Resource Partitioning in a Complex Fauna". Ecology, 49(4), 704-726.

Examples


# load the data and build the correct network from the model string.
data(lizards)
res = empty.graph(names(lizards))
modelstring(res) = "[Species][Diameter|Species][Height|Species]"
plot(res)

table(lizards[, c(3,2,1)])
# , , Species = Sagrei
#
#       Diameter
# Height narrow wide
#   high     86   35
#   low      32   11
#
# , , Species = Distichus
#
#       Diameter
# Height narrow wide
#   high     73   70
#   low      61   41

## Not run: 
# This data set is useful as it offers nominal values for
# the conditional mutual information and X^2 tests.

attach(lizards)
ci.test(Height, Diameter, Species, test = "mi")
#
#       Mutual Information (discrete)
#
# data:  Height ~ Diameter | Species
# mi = 2.0256, df = 2, p-value = 0.3632
# alternative hypothesis: true value is greater than 0
ci.test(Height, Diameter, Species, test = "x2")
#
#       Pearson's X^2
#
# data:  Height ~ Diameter | Species
# x2 = 2.0174, df = 2, p-value = 0.3647
# alternative hypothesis: true value is greater than 0
## End(Not run)
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