estimateParameter {CALIB} | R Documentation

## Estimate model parameter from spikes

### Description

Estimate the calibration model parameters according to the known concentration and the measured intensities of external control spikes on each array.

### Usage

     estimateParameter(spike, RG, bc = FALSE, area = TRUE, errormodel = "M")

### Arguments

`spike` | a `SpikeList` object.
`RG` | a `RGList_CALIB` object.
`bc` | a logical value. `TRUE` means background corrected measured intensities are used. Default is `FALSE`.
`area` | a logical value. `TRUE` means spot area is used to calculate measured intensities. Namly, measured intensities are calculated by foreground intensities(or background corrected intensities, if bc is `TRUE` ) multiply spot area. `FALSE` means spot area is not used. Default is `TRUE` .
`errormodel` | a character to indicate the distribution of spot capacity. "A" means spot capacity is additive. "M" means spot capacity is multiplicative. Default is "M".

### Details

This function estimates calibration model parameters. In this function, the model parameters are estimated separately for each microarray, based on the measured intensities of the external control spikes and their known concentration in the hybridization solution. It accepts spike measured intensities and concentration from `spike` argument, which is an object of `SpikeList` class.

It supports different ways to calculate the measured intensities. Arguments `bc` and `area` are logical and their combinations is used for specifying four differents ways. `bc` indicates using background correction or not. `area` indicates multiplying spot area or not. The default value of these two arguments are `bc` = FALSE and `area` = TRUE.

The argument `errormodel` is to specify the distribution of spot capacity of each array. The spot capacity is either additive or multiplicative. Whichever distribution is more appropriate will depend largely on the type of microarray slide and spotting procedure used. The spot parameters mus and sigmas can be considered equal for all measurements of a single array.

The argument `RG` is for calculating the maximum intensity of each array. These maximum intensities are used to estimate the upper saturation level of each array.

More details please refer to the reference literature.

### Value

An `ParameterList` object containing the components:

`MuS` | matrix containing MuS for each array.
`Ka` | matrix containing Ka for each array.
`P1` | matrix containing P1 of each dye for each array.
`P2` | matrix containing P2 of each dye for each array.
`SigmaA` | matrix containing sigma additive for each array.
`SigmaM` | matrix containing sigma multiplicative for each array.
`SigmaS` | matrix containing sigma spoterror for each array.
`SpotError` | matrix containing the spot error of each spot for each array.
`Method` | boolean values indicating the way to calculate the measured intensities.
`ErrorModel` | character `"M"` or `"A"` to indicate the type of spot capacity distribution.

### Author(s)

Hui Zhao

### References

Engelen, K., Naudts, B., DeMoor, B., Marchal, K. (2006) A calibration method for estimating absolute expression levels from microarray data. Bioinformatics 22: 1251-1258.

### Examples

    # load data: RG and spike
    data(RG)
    data(spike)

    # for the measured itensities, take the default bc=FALSE and area=TRUE.
    # use multiplicative spot error model
    parameter <- estimateParameter(spike,RG)

[Package CALIB version 1.4.0 Index]