ashtrees


This dataset comes from a study of symptoms of crown dieback, cankers
and symptoms caused by other pathogens and pests in ash trees (Fraxinus
excelsior). In all 454 trees were observed in two plots. There are 8
categorical variables, 6 of which are binary and two are trichotomous  
with values representing increasing severity of symptoms, and one
continuous variable, tree diameter at breast height (DBH).   


datasets

The 'gRbase' package provides general features
which are used by other graphical modelling packages, in particular
by the packages 'gRain', 'gRim' and 'gRc'.

'gRbase' contains several datasets relevant for use in connection with
graphical models. Almost all datasets used in the book Graphical
Models with R (2012) are contained in 'gRbase'.

'gRbase' implements several graph algorithms (based mainly on
representing graphs as adjacency matrices - either in the form
of a standard matrix or a sparse matrix). Some graph
algorithms are:
(i) maximum cardinality search (for marked and unmarked graphs).
(ii) moralize.
(iii) triangulate.
(iv) junction tree.

'gRbase' facilitates array operations,

'gRbase' implements functions for testing for conditional independence.

'gRbase' illustrates how hierarchical log-linear models may be
implemented and describes concept of graphical meta
data. These features, however, are not maintained anymore and
remains in 'gRbase' only because there exists a paper describing
these facilities: A Common Platform for Graphical Models in R:
The 'gRbase' Package, Journal of Statistical Software, Vol 14,
No 17, 2005.

NOTICE Proper functionality of 'gRbase' requires that the packages graph,
'Rgraphviz' and 'RBGL' are installed from 'bioconductor'; for
installation instructions please refer to the webpage given below.

Søren Højsgaard

gRbase

A Package for Graphical Modelling in R

ashtrees function

A data frame with 454 observations on the following 9 variables.
  <dl>
    <dt><code>plot</code></dt><dd>a factor with levels <code>2</code> <code>6</code></dd> <dt><code>dieback</code></dt><dd>a factor with levels <code>0</code> <code>1</code> <code>2</code></dd> <dt><code>dead50</code></dt><dd>a factor with levels <code>0</code> <code>0.5</code> <code>1</code></dd> <dt><code>bushy</code></dt><dd>a factor with levels <code>0</code> <code>1</code></dd> <dt><code>canker</code></dt><dd>a factor with levels <code>BRNCH</code> <code>MAIN</code> <code>NONE</code></dd> <dt><code>wilt</code></dt><dd>a factor with levels <code>0</code> <code>1</code></dd> <dt><code>roses</code></dt><dd>a factor with levels <code>0</code> <code>1</code></dd> <dt><code>discolour</code></dt><dd>a factor with levels <code>0</code> <code>1</code></dd> <dt><code>dbh</code></dt><dd>a numeric vector</dd> </dl> 

ashtrees: Crown dieback in ash trees

Description

Usage

Arguments

Format

References

Examples