\title{Comparison of distributions of sample groups}
  wilcoxOrKruskalOnA(A, colAnnot, annot)
  \item{A}{A matrix of dimensions 'samples x components'
  containing the sample contributions}

  \item{annot}{A matrix of dimensions 'samples x variables'
  containing the sample annotations}

  \item{colAnnot}{The name of the column of \code{annot} to
  be considered}
  A vector of p-values
  Compare the sample contributions according to their
  annotation level across the components.
  Wilcoxon or Kruskal-Wallis tests are performed depending
  on the number of levels in the considered annotation.
  Anne Biton
  \code{wilcox.test}, \code{kruskal.test}