Introduction - Bayesian Networks in R: With Applications in Systems Biology - page 8

Perch Height (Sagrei) Perch Height (Distichus)

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0 0

high low high low

Perch Diameter (Sagrei) Perch Diameter (Distichus)

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narrow wide narrow wide

Fig. 1.3 Barplots for the perch height and diameter of sagrei and distichus lizards

are considering. A simple way to plot the frequencies associated with Height and
Diameter for each species is to use a barplot .
> Sagrei.lizards =
+ lizards[lizards$Species == "Sagrei", ]
> Distichus.lizards =
+ lizards[lizards$Species == "Distichus", ]
> par(mfrow = c(2, 2))
> plot(Sagrei.lizards[, "Height"],
+ main = "Perch Height (Sagrei)")
> plot(Distichus.lizards[, "Height"],
+ main = "Perch Height (Distichus)")
> plot(Sagrei.lizards[, "Diameter"],
+ main = "Perch Diameter (Sagrei)")
> plot(Distichus.lizards[, "Diameter"],
+ main = "Perch Diameter (Distichus)")
Figure 1.3 shows the plot generated be the commands above. The first two com-
mands extract from the data set the subsets of observations corresponding to each
species. par is then used to split the plot area into four quadrants, arranged in a lay-
out with 2 rows and 2 columns. Each quadrant holds one of the barplots, which are