RankingSam: Ranking based on the SAM statistic

Description Usage Arguments Value Note Author(s) References See Also Examples

Description

A wrapper function to the samr package.

Usage

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RankingSam(x, y, type = c("unpaired", "paired", "onesample"), pvalues = TRUE, gene.names = NULL, ...)

Arguments

x

A matrix of gene expression values with rows corresponding to genes and columns corresponding to observations or alternatively an object of class ExpressionSet.
If type = paired, the first half of the columns corresponds to the first measurements and the second half to the second ones. For instance, if there are 10 observations, each measured twice, stored in an expression matrix expr, then expr[,1] is paired with expr[,11], expr[,2] with expr[,12], and so on.

y

If x is a matrix, then y may be a numeric vector or a factor with at most two levels.
If x is an ExpressionSet, then y is a character specifying the phenotype variable in the output from pData.
If type = "paired", take care that the coding is analogously to the requirement concerning x.

type
"unpaired":

two-sample test.

"paired":

paired test. Take care that the coding of y is correct (s. above).

"onesample":

y has only one level. Test whether the true mean is different from zero.

pvalues

Should p-values be computed ? Default is TRUE.

gene.names

An optional vector of gene names.

...

Further arguments to be passed to samr. Consult the help of the samr package for details.

Value

An object of class GeneRanking.

Note

The computing time is relatively high, due to the fact that permutation statistics are generated.

Author(s)

Martin Slawski
Anne-Laure Boulesteix

References

Tusher, V.G., Tibshirani, R., and Chu, G. (2001).
Significance analysis of microarrays applied to the ionizing radiation response. PNAS, 98, 5116-5121.

Schwender, H., Krause, A. and Ickstadt, K. (2003).
Comparison of the Empirical Bayes and the Significance Analysis of Microarrays. Technical Report, University of Dortmund.

See Also

RepeatRanking, RankingTstat, RankingFC, RankingWelchT, RankingWilcoxon, RankingBaldiLong, RankingFoxDimmic, RankingLimma, RankingEbam, RankingWilcEbam, RankingShrinkageT, RankingSoftthresholdT, RankingPermutation

Examples

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### Load toy gene expression data
data(toydata)
### class labels
yy <- toydata[1,]
### gene expression
xx <- toydata[-1,]
### run RankingSam
sam <- RankingSam(xx, yy, type="unpaired")

GeneSelector documentation built on May 1, 2019, 11:35 p.m.