ellipseCA | R Documentation |

Draw confidence ellipses in CA around rows and/or columns.

```
ellipseCA (x, ellipse=c("col","row"), method="multinomial", nbsample=100,
axes=c(1,2), xlim=NULL, ylim=NULL, col.row="blue", col.col="red",
col.row.ell=col.row, col.col.ell=col.col,
graph.type = c("ggplot","classic"), ggoptions = NULL, ...)
```

`x` |
an object of class CA |

`ellipse` |
a vector of character that defines which ellipses are drawn |

`method` |
the method to construct ellipses (see details below) |

`nbsample` |
number of samples drawn to evaluate the stability of the points |

`axes` |
a length 2 vector specifying the components to plot |

`xlim` |
range for the plotted 'x' values, defaulting to the range of the finite values of 'x' |

`ylim` |
range for the plotted 'y' values, defaulting to the range of the finite values of 'y' |

`col.row` |
a color for the rows points |

`col.col` |
a color for columns points |

`col.row.ell` |
a color for the ellipses of rows points (the color "transparent" can be used if an ellipse should not be drawn) |

`col.col.ell` |
a color for the ellipses of columns points (the color "transparent" can be used if an ellipse should not be drawn) |

`graph.type` |
a character that gives the type of graph used: "ggplot" or "classic" |

`ggoptions` |
a list that gives the graph options when grah.type="ggplot" is used. See the optines and the default values in the details section |

`...` |
further arguments passed to or from the plot.CA function, such as title, invisible, ... |

With `method="multinomial"`

, the table X with the active elements is taken as a reference. Then new data tables are drawn in the following way:
N (the sum of X) values are drawn from a multinomial distribution with theoretical frequencies equals to the values in the cells divided by N.

With `method="boot"`

, the values are bootstrapped row by row: Ni (the sum of row i in the X table) values are taken in a vector with Nij equals to column j (with j varying from 1 to J).

Thus `nbsample`

new datasets are drawn and projected as supplementary rows and/or supplementary columns. Then confidence ellipses are drawn for each elements thanks to the `nbsample`

supplementary points.

Returns the factor map with the joint plot of CA with ellipses around some elements.

Francois Husson francois.husson@institut-agro.fr

Lebart, L., Morineau, A. and Piron, M. (1995) Statistique exploratoire multidimensionnelle, *Dunod*.

`plot.CA`

, `CA`

```
data(children)
res.ca <- CA (children, col.sup = 6:8, row.sup = 15:18)
## Ellipses for all the active elements
ellipseCA(res.ca)
## Ellipses around some columns only
ellipseCA(res.ca,ellipse="col",col.col.ell=c(rep("red",2),rep("transparent",3)),
invisible=c("row.sup","col.sup"))
```

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