On this Picostat.com statistics page, you will find information about the toxicity data set which pertains to Toxicity of Carboxylic Acids Data. The toxicity data set is found in the robustbase R package. You can load the toxicity data set in R by issuing the following command at the console data("toxicity"). This will load the data into a variable called toxicity. If R says the toxicity data set is not found, you can try installing the package by issuing this command install.packages("robustbase") and then attempt to reload the data. If you need to download R, you can go to the R project website. You can download a CSV (comma separated values) version of the toxicity R data set. The size of this file is about 2,242 bytes.

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))

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Dataset imported from https://www.r-project.org.