# Tools for Meta-analysis of gene expression data.

### Description

A small number of meta-analysis functions for comparing two gene expression experiments are provided.

### Usage

1 2 3 |

### Arguments

`d` |
A vector of t-statistics, i.e. the output of |

`n` |
The number of t-statistics. |

`data` |
The data used to compute t-statistics, either a |

`categ` |
A vector of 0's and 1's indicating group membership. |

`ng1` |
The number of samples in group 1. |

`ng2` |
The number of samples in group 2. |

### Details

The functions `getdF`

compute t-test statistics
for the input data and group membership (note that group membership
must be indicated by a vector of 0's and 1's).

The function `dstar`

computes an unbiased estimate of the t-test.
The function `sigmad`

computes the variance estimate of
`dstar`

.

### Value

The different functions have different return values, but generally they are vectors of the requested quantities.

### Author(s)

L. Lusa, R. Gray and R. Gentleman

### References

Choi et al, Combining multiple microarray studies and modeling interstudy variation. Bioinformatics, 2003, i84-i90.

### Examples

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