imp4p (version 1.2)

impute.rand: Imputation of peptides with a random value.

Description

For each row (peptide), this function imputes missing values by random values following a Gaussian distribution.

Usage

impute.rand(tab, conditions)

Arguments

tab

A data matrix containing numeric and missing values. Each column of this matrix is assumed to correspond to an experimental sample, and each row to an identified peptide.

conditions

A vector of factors indicating the biological condition to which each column (experimental sample) belongs.

Value

The input matrix tab with imputed values instead of missing values.

Details

For each row (peptide), this function imputes missing values by random values following a Gaussian distribution centered on the mean of the observed values in the condition for the specific peptide and with a standard deviation equal to the first quartile of the distribution of the standard deviation the values observed for all the peptides. Rows with only missing values in a condition are not imputed (the impute.pa function can be used for this purpose).

Examples

# NOT RUN {
#Simulating data
res.sim=sim.data(nb.pept=2000,nb.miss=600);

#Imputation of the simulated data set with random values
data.rand=impute.rand(res.sim$dat.obs,res.sim$conditions);
# }