bca function

Between-Class Analysis

Performs a particular case of a Principal Component Analysis with respect to Instrumental Variables (pcaiv), in which there is only a single factor as explanatory variable.

## S3 method for class 'dudi'
bca(x, fac, scannf = TRUE, nf = 2, ...)

Arguments

• x: a duality diagram, object of class dudi from one of the functions dudi.coa, dudi.pca,...
• fac: a factor partitioning the rows of dudi$tab in classes
• scannf: a logical value indicating whether the eigenvalues barplot should be displayed
• nf: if scannf FALSE, a numeric value indicating the number of kept axes
• ...: further arguments passed to or from other methods

Returns

Returns a list of class dudi, subclass 'between' containing - tab: a data frame class-variables containing the means per class for each variable

• cw: a numeric vector of the column weigths

• lw: a numeric vector of the class weigths

• eig: a numeric vector with all the eigenvalues

• rank: the rank of the analysis

• nf: an integer value indicating the number of kept axes

• c1: a data frame with the column normed scores

• l1: a data frame with the class normed scores

• co: a data frame with the column coordinates

• li: a data frame with the class coordinates

• call: the matching call

• ratio: the bewteen-class inertia percentage

• ls: a data frame with the row coordinates

• as: a data frame containing the projection of inertia axes onto between axes

References

Dolédec, S. and Chessel, D. (1987) Rythmes saisonniers et composantes stationnelles en milieu aquatique I- Description d'un plan d'observations complet par projection de variables. Acta Oecologica, Oecologia Generalis, 8 , 3, 403--426.

Note

To avoid conflict names with the base:::within function, the function within is now deprecated and removed. To be consistent, the between function is also deprecated and is replaced by the method bca.dudi of the new generic bca function.

Author(s)

Daniel Chessel

Anne-Béatrice Dufour anne-beatrice.dufour@univ-lyon1.fr

Examples

data(meaudret)
pca1 <- dudi.pca(meaudret$env, scan = FALSE, nf = 4)
pca2 <- dudi.pca(meaudret$spe, scal = FALSE, scan = FALSE, nf = 4)
bet1 <- bca(pca1, meaudret$design$site, scan = FALSE, nf = 2)
bet2 <- bca(pca2, meaudret$design$site, scan = FALSE, nf = 2)
  
if(adegraphicsLoaded()) {
  g1 <- s.class(pca1$li, meaudret$design$site, psub.text = "Principal Component Analysis (env)",
    plot = FALSE)
  g2 <- s.class(pca2$li, meaudret$design$site, psub.text = "Principal Component Analysis (spe)",
    plot = FALSE)
  g3 <- s.class(bet1$ls, meaudret$design$site, psub.text = "Between sites PCA (env)", plot = FALSE)
  g4 <- s.class(bet2$ls, meaudret$design$site, psub.text = "Between sites PCA (spe)", plot = FALSE)
  G <- ADEgS(list(g1, g2, g3, g4), layout = c(2, 2))
  
} else {
  par(mfrow = c(2, 2))
  s.class(pca1$li, meaudret$design$site, sub = "Principal Component Analysis (env)", csub = 1.75)
  s.class(pca2$li, meaudret$design$site, sub = "Principal Component Analysis (spe)", csub = 1.75)
  s.class(bet1$ls, meaudret$design$site, sub = "Between sites PCA (env)", csub = 1.75)
  s.class(bet2$ls, meaudret$design$site, sub = "Between sites PCA (spe)", csub = 1.75)
  par(mfrow = c(1, 1))
}

coib <- coinertia(bet1, bet2, scann = FALSE)
plot(coib)