toxicity: Toxicity of Carboxylic Acids Data
In robustbase: Basic Robust Statistics

toxicity

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, package="robustbase")

Format

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

toxicity: aquatic toxicity, defined as \log(IGC_{50}^{-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: https://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))

robustbase documentation built on Sept. 3, 2025, 3:01 a.m.