toxicity {robustbase} | R Documentation

## Toxicity of Carboxylic Acids Data

### Description

The aim of the experiment was to predict the toxicity of carboxylic acids on the basis of several molecular descriptors.

### Usage

    data(toxicity)

### Format

A data frame with 38 observations on the following 10 variables which are attributes for carboxylic acids:

`toxicity`

  aquatic toxicity, defined as log(IGC50^(-1)); typically the “response”.

`logKow`

  log Kow, the partition coefficient

`pKa`

  pKa: the dissociation constant

`ELUMO`

  Energy of the lowest unoccupied molecular orbital

`Ecarb`

  Electrotopological state of the carboxylic group

`Emet`

  Electrotopological state of the methyl group

`RM`

  Molar refractivity

`IR`

  Refraction index

`Ts`

  Surface tension

`P`

  Polarizability

### Source

The website accompanying the MMY-book: http://www.wiley.com/legacy/wileychi/robust_statistics

### References

Maguna, F.P., Núñez, M.B., Okulik, N.B. and Castro, E.A. (2003) Improved QSAR analysis of the toxicity of aliphatic carboxylic acids; Russian Journal of General Chemistry 73, 1792–1798.

### Examples

    data(toxicity)
    summary(toxicity)
    plot(toxicity)
    plot(toxicity ~ pKa, data = toxicity)

    ## robustly scale the data (to scale 1) using Qn
    (scQ.tox <- sapply(toxicity, Qn))
    scTox <- scale(toxicity, center = FALSE, scale = scQ.tox)
    csT <- covOGK(scTox, n.iter = 2,
                  sigmamu = s_Qn, weight.fn = hard.rejection)
    as.dist(round(cov2cor(csT$cov), 2))

[Package robustbase version 0.92-8 Index]