## Decomposition of inertia (i.e. contributions) in multivariate methods

### Description

Computes the decomposition of inertia to measure the contributions of row and/or columns in multivariate methods

### Usage

```## S3 method for class 'dudi'
inertia(x, row.inertia = FALSE, col.inertia = FALSE, ...)
## S3 method for class 'inertia'
print(x, ...)
## S3 method for class 'inertia'
summary(object, subset = 5, ...)
```

### Arguments

 `x, object` a duality diagram, object of class `dudi` for `inertia.dudi`. An object of class `inertia` for the methods `print` and `summary` `row.inertia` if TRUE, returns the decomposition of inertia for the rows `col.inertia` if TRUE, returns the decomposition of inertia for the columns `subset` the number of rows and/or columns to display in the summary `...` further arguments passed to or from other methods

### Details

Contributions are printed in percentage and the sign is the sign of the coordinates

### Value

An object of class `inertia`, i.e. a list containing :

 `TOT` repartition of the total inertia between axes `row.contrib` contributions of the rows to the total inertia `row.abs` absolute contributions of the rows (i.e. decomposition per axis) `row.rel` relative contributions of the rows `row.cum` cumulative relative contributions of the rows (i.e. decomposition per row) `col.contrib` contributions of the columns to the total inertia `col.abs` absolute contributions of the columns (i.e. decomposition per axis) `col.rel` relative contributions of the columns `col.cum` cumulative relative contributions of the columns (i.e. decomposition per column)

### Author(s)

Daniel Chessel
Stephane Dray stephane.dray@univ-lyon1.fr
Anne B Dufour anne-beatrice.dufour@univ-lyon1.fr

### References

Lebart, L., Morineau, A. and Tabart, N. (1977) Techniques de la description statistique, méthodes et logiciels pour la description des grands tableaux, Dunod, Paris, 61–62.

Volle, M. (1981) Analyse des données, Economica, Paris, 89–90 and 118

Lebart, L., Morineau, L. and Warwick, K.M. (1984) Multivariate descriptive analysis: correspondence and related techniques for large matrices, John Wiley and Sons, New York.

Greenacre, M. (1984) Theory and applications of correspondence analysis, Academic Press, London, 66.

Rouanet, H. and Le Roux, B. (1993) Analyse des données multidimensionnelles, Dunod, Paris, 143–144.

Tenenhaus, M. (1994) Méthodes statistiques en gestion, Dunod, Paris, p. 160, 161, 166, 204.

Lebart, L., Morineau, A. and Piron, M. (1995) Statistique exploratoire multidimensionnelle, Dunod, Paris, p. 56,95-96.

### Examples

```data(housetasks)
coa1 <- dudi.coa(housetasks, scann = FALSE)
res <- inertia(coa1, col = TRUE, row = FALSE)
res
summary(res)
```