ma2D {marray} | R Documentation

## Stratified bivariate robust local regression

### Description

This function performs robust local regression of a variable `z` on predictor variables `x` and `y`, separately within values of a fourth variable `g`. It is used by `maNorm2D` for 2D spatial location normalization.

### Usage

    ma2D(x, y, z, g, w=NULL, subset=TRUE, span=0.4, ...)

### Arguments

`x` | A numeric vector of predictor variables.
`y` | A numeric vector of predictor variables.
`z` | A numeric vector of responses.
`g` | Variables used to stratify the data.
`w` | An optional numeric vector of weights.
`subset` | A "logical" or "numeric" vector indicating the subset of points used to compute the fits.
`span` | The argument `span` which controls the degree of smoothing in the `loess` function.
`...` | Misc arguments

### Details

`z` is regressed on `x` and `y`, separately within values of `g` using the `loess` function.

### Value

A numeric vector of fitted values.

### Author(s)

Sandrine Dudoit, http://www.stat.berkeley.edu/~sandrine.

### References

S. Dudoit and Y. H. Yang. (2002). Bioconductor R packages for exploratory analysis and normalization of cDNA microarray data. In G. Parmigiani, E. S. Garrett, R. A. Irizarry and S. L. Zeger, editors, The Analysis of Gene Expression Data: Methods and Software, Springer, New York.

### See Also

`maNormMain`, `maNorm2D`, `loess`.

### Examples

    # See examples for maNormMain.

[Package marray version 1.70.0 Index]