# outliers: Outliers detection In FactoInvestigate: Automatic Description of Factorial Analysis

## Description

Detection of singular individuals that concentrates too much inertia.

## Usage

 ```1 2``` ```outliers(res, file = "", Vselec = "cos2", Vcoef = 1, nmax = 10, figure.title = "Figure", graph = TRUE, cex = 0.7, options = NULL) ```

## Arguments

 `res` an object of class PCA or MCA. `file` a numerical vector giving the factorial dimensions for with to compute the eigen values calculation. `Vselec` the variables to select ; see the details section. `Vcoef` a numerical coefficient to adjust the variables selection rule ; see the details section. `nmax` an integer giving the maximum number of variables to illustrate each outlier (by default 10). `figure.title` the text label to add before graph title. `graph` a boolean : if `TRUE`, graphs are plotted. `cex` an optional argument for the generic plot functions, used to adjust the size of the elements plotted. `options` a character string that gives the output options for the figures. If NULL, `options="r, echo = FALSE, fig.align = 'center', fig.height = 3.5, fig.width = 5.5"` for linux and Mac and `options="r, echo = FALSE, fig.height = 3.5, fig.width = 5.5"` for Windows

## Details

The algorithm detects an individual as an outlier if its contribution to the plane if higher to 3 standard deviation.

The `Vselec` argument is used in order to select a part of the variables that are drawn and described. For example, you can use either :
- `Vselec = 1:5` then the variables numbered 1 to 5 are drawn.
- `Vselec = c("name1","name5")` then the variables named `name1` and `name5` are drawn.
- `Vselec = "contrib 10"` then the 10 active or illustrative variables that have the highest contribution on the 2 dimensions of the plane are drawn.
- `Vselec = "contrib"` then the optimal number of active or illustrative variables that have the highest contribution on the 2 dimensions of the plane are drawn.
- `Vselec = "cos2 5"` then the 5 active or illustrative variables that have the highest cos2 on the 2 dimensions of the plane are drawn.
- `Vselec = "cos2 0.8"` then the active or illustrative variables that have a `cos2` higher to `0.8` on the plane are drawn.
- `Vselec = "cos2"` then the optimal number of active or illustrative variables that have the highest cos2 on the 2 dimensions of the plane are drawn.

The `Vcoef` argument is used in order to adjust the selection of the variables when based on `Vselec = "contrib"` or `Vselec = "cos2"`. For example :
- if `Vcoef = 2`, the threshold is 2 times higher, and thus 2 times more restrictive.
- if `Vcoef = 0.5`, the threshold is 2 times lower, and thus 2 times less restrictive.

## Value

 `new.res` the res object without the outliers (they are completely eliminated). `res.out` the res object with the outliers as supplementary individuals. `memory` the original res object. `N` the number of outliers. `ID` the label of outliers.

## Author(s)

Simon Thuleau and Francois Husson

## Examples

 ```1 2 3 4``` ```require(FactoMineR) data(decathlon) res.pca = PCA(decathlon, quanti.sup = c(11:12), quali.sup = c(13), graph = FALSE) outliers(res.pca, file = "PCA.Rmd") ```

FactoInvestigate documentation built on May 5, 2018, 5:04 p.m.