iqr {LPE}R Documentation

Inter-quartile range

Description

Finds inter-quartile range of the data = {75th percentile - 25th percentile}.

Usage

  iqr(x)

Arguments

x x is a vector for which IQR has to be found.

Value

Returns a numeric value representing the difference of 75th percentile and 25th percentile of the vector. It is used for normalization across the chips - basic assumption is that net differential expression of the middle half of the genes in microarray experiment is zero, which is conservative assumption as typically only 5-10 differential expression.

References

J.K. Lee and M.O.Connell(2003). An S-Plus library for the analysis of differential expression. In The Analysis of Gene Expression Data: Methods and Software. Edited by G. Parmigiani, ES Garrett, RA Irizarry ad SL Zegar. Springer, NewYork.

Jain et. al. (2003) Local pooled error test for identifying differentially expressed genes with a small number of replicated microarrays, Bioinformatics, 1945-1951.

See Also

lpe

Examples

  library(LPE)
  # Loading the LPE library
 
  iqr(1:5) 

[Package LPE version 1.1.5 Index]