Provides functions and command-line user interface to generate allocation sequence 
             by response-adaptive randomization for clinical trials. The package currently supports 
             two families of frequentist response-adaptive randomization procedures, Doubly Adaptive 
             Biased Coin Design ('DBCD') and Sequential Estimation-adjusted Urn Model ('SEU'), for 
             binary and normal endpoints. One-sided proportion (or mean) difference and Chi-square 
             (or 'ANOVA') hypothesis testing methods are also available in the package to  facilitate 
             the inference for treatment effect. Additionally, the package provides comprehensive and 
             efficient tools to allow one to evaluate and  compare the performance of randomization 
             procedures and tests based on various criteria. For example, plots for relationship among 
             assumed treatment effects,  sample size, and power are provided. Five allocation functions 
             for 'DBCD' and six addition rule functions for 'SEU' are implemented to target allocations 
             such as 'Neyman', 'Rosenberger' Rosenberger et al. (2001) 
             <doi:10.1111/j.0006-341X.2001.00909.x> and 'Urn' allocations.

Allows calculation of rarity weights for species and indices of rarity for assemblages of species according to different methods (Leroy et al. 2012, Insect. Conserv. Divers. 5:159-168 <doi:10.1111/j.1752-4598.2011.00148.x>; Leroy et al. 2013, Divers. Distrib. 19:794-803 <doi:10.1111/ddi.12040>).

Interface to easily access data via the United States Department of Agriculture (USDA)'s Agricultural Resource Management Survey (ARMS) 
  Data API <https://www.ers.usda.gov/developer/data-apis/arms-data-api/>. The downloaded data can be saved for later off-line use. 
  Also provide relevant information and metadata for each of the input variables needed for sending the data inquery.

Previously an R wrapper of the 'ARPACK' library
    <http://www.caam.rice.edu/software/ARPACK/>, and now a shell of the
    R package 'RSpectra', an R interface to the 'Spectra' library
    <http://yixuan.cos.name/spectra/> for solving large scale
    eigenvalue/vector problems. The current version of 'rARPACK'
    simply imports and exports the functions provided by 'RSpectra'.
    New users of 'rARPACK' are advised to switch to the 'RSpectra' package.