plotVolcano {aspi} | R Documentation |

## Volcano plot

### Description

Produces scatterplot of statistical significance vs fold difference in parasite abundance between left and right.

### Usage

```
plotVolcano(x, test = "G", pAdj = "BH", sigThresh = 0.05, ...)
```

### Arguments

`x` |
a matrix or data frame with two numeric columns; first column is for left-side and 2nd column for right-side. Identifiers for hosts can be provided as row names. |

`test` |
if set to "G" (default) a G-test is performed; otherwise an exact binomial test is performed. |

`pAdj` |
method for correcting p-values for multiple comparisons. If set to "BH" (default), Benjamini & Hochberg's procedure is used to control the false discovery rate (FDR); otherwise Holm's methos is used to control the familywise error rate (FWER). |

`sigThresh` |
significance threshold (defaults to 0.05); p-values below this value will be called significant. |

`...` |
optional further arguments and graphical parameters passed to plot. |

### Details

plot.Volcano creates a volcano plot, i.e. a scatterplot of statistical significance (-log10(p-value)) vs fold difference (log2 ratio - as calculated for the histogram above) in parasite abundance between left and right. Each point in the scatterplot represents the parasite distribution in an individual host. A dashed horizontal line represents the user-defined p-value threshold for significance. If a parasite distribution deviates significantly from symmetry it is shown as a red square, otherwise as a blue circle.

### Examples

```
plotVolcano(diplostomum_eyes_excl_lenses)
plotVolcano(diplostomum_eyes_excl_lenses, test="G", pAdj="BH", sigThresh=0.1,
main="Diplostomum metacercariae in eyes of ruffe")
```

*aspi*version 0.2.0 Index]