Developed by the U.S. Geological Survey, NADA for R is a library package for the R environment for graphics and statistics. All functions are presented within in a consistent, user-friendly framework and can be used to:
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plot data,
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generate summary statistics,
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compute exceedance probabilities, and
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perform hypothesis tests on data containing multiple censoring thresholds (a.k.a nondetects, or less-thans).
The package contains data and analysis methods described in the book: Nondetects and Data Analysis: Statistics for Censored Environmental Data, Helsel (2005).