Learn R Programming

sn (version 0.30)

SN: The library `sn': summary information

Description

This library provides functions related to the skew-normal (SN) and the skew-t (ST) probability distributions, both for the univariate and for the the multivariate case.

Arguments

Functions

The library includes several functions, a number of which are intended as services to other functions, not really to be called directly by the users. The following ones are those more relevant for practical use.

SN distribution: dsn, psn, qsn, rsn, cp.to.dp, dp.to.cp, sn.mle, sn.em,for the univariate case, and dmsn, pmsn, rmsn, msn.fit, msn.mle, dsn2.plot for the multivariate case.

ST distribution: dst, pst, rst, st.mle,for the univariate case, and dmst,pmst, rmst, mst.fit, mst.mle, dst2.plot for the multivariate case.

It is suggested that a user starts by reading the documentation of (some of) these.

Requirements

R 1.0.1. A few functions require library(mvtnorm); these are: pmsn, pmst, pst,

Version

The version level of the library is given by the command print(.sn.version). The most recent version of the library can be obtained from the WWW page: http://azzalini.stat.unipd.it/SN which also contains other related material

Manual

There is no manual besides on-line documentation and its derived versions. The papers listed below provide background information.

Author

Adelchi Azzalini, Dipart. Scienze Statistiche, Universit� di Padova, Italia. Please send comments, error reports, etc. to adelchi.azzalini@unipd.it

Acknowledgements

The library has evolved through several version developed over some years.

For versions up to 0.20, the following people and institutions have contributed. Many thanks go to Antonella Capitanio for testing the procedures, and to Brian Ripley and Martin Maechler for useful advice on R. The function num.deriv is based on a similar function written by Monica Chiogna. This software and part of the associated theoretical work has been developed while the author was at the Nuffield College, Oxford, under the Jemolo Fellowship scheme; the generous support of the college is gratefully acknowledged. Additional support for the development of the theoretical research work has been provided by the "Consiglio Nazionale delle Ricerche" of Italy, grant no.97.01331.CT10.

Versions 0.21 to 0.30 have been supported by "MIUR", Italy, under grant scheme PRIN 2000. Again, thanks to Antonella Capitanio for additional testing of the new version of the library.

LICENCE

This library and its documentation are usable under the terms of the "GNU General Public License", a copy of which is distributed with the package.

References

Azzalini, A. (1985). A class of distributions which includes the normal ones. Scand. J. Statist. 12, 171--178.

Azzalini, A. (1986). Further results on a class of distributions which includes the normal ones. Statistica 46,199--208.

Azzalini, A. and Dalla Valle, A. (1996). The multivariate skew-normal distribution. Biometrika 83, 715--726.

Azzalini, A. and Capitanio, A. (1999). Statistical applications of the multivariate skew-normal distribution. J.Roy.Statist.Soc. B 61, 579--602.

Azzalini, A. and Capitanio, A. (2002). Distributions generated by perturbation of symmetry with emphasis on a multivariate skew-t distribution. Submitted to J.Roy. Statist. Soc.