NADA for R

R is a free and freely-available implementation of the S-language for statistical computing originally developed by John Chambers and others at Bell Labs. It has a Unix-like interface, but compiled versions run under the Unix, Windows and Macintosh operating systems. It is a powerful environment for statistical computing -- newly-developed methods are frequently released with an R implementation. R operates under the GNU license and contributed packages are developed by volunteers worldwide.

NADA for R ( See this link ) is a user-contributed package available from the CRAN (Comprehensive R Archive Network) site. It was written by Lopaka Lee of the US Geological Survey, and implements the procedures found in the textbook Statistics for Censored Environmental Data using Minitab and R by Helsel (2012), published by Wiley. Methods are included for computing descriptive statistics, hypothesis tests, correlation and regression for left-censored (nondetect) data.

USER GUIDE: A user's guide to NADA for R is available on our NADA downloads page. The guide is the handout from our August 2006 NADA for R workshop for the American Statistical Association. Through example exercises, the use of the NADA for R package is demonstrated. Datasets used in the exercises come with the NADA for R package, so you can perform each exercise yourself to become familiar with all the NADA for R parametric and nonparametric functions.

USCORES FUNCTION: An R uscores script for censored data is now available on the NADA downloads page. This is not included within the NADA for R package.