Description Usage Arguments Details Value Note Author(s) References See Also Examples
Species richnesses are computed as the cumulative value over all samples. Richnesses are compared by mean of a randomization test without controlling for differences of sampling regime of communities density.
1 |
com1 |
A first species-sample matrix (community 1). Rows correspond to samples whereas columns stand for species. |
com2 |
A second species-sample matrix (community 2). Rows correspond to samples whereas columns stand for species. |
nrandom |
Number of randomizations to be performed. Default fixed to 99. |
pr1 |
Lower probability level for quantile computations. Default fixed to 0.025. |
pr2 |
Higher probability level for quantile computations. Default fixed to 0.975. |
verbose |
If |
If the observed richness for community 1 ≥ observed value for community 2, c2cv
returns a probability p
estimated as the number of randomizations for which the observed value for community 1 ≥ observed value for community 2 divided by the number of randomization + 1. Similarly, if the observed value for community 1 ≤ observed value for community 2, p
corresponds to the frequency of such situation in the randomizations.
If verbose==TRUE
c2cm
returns a data frame and a vector with the randomized values. Otherwise, only the data frame is returned.
res |
A data frame with the outputs of the randomization test: |
rand |
A vector of |
The observed difference between populations is included in the numerator and the denominator when computing the probability p
. This is justified because if the null hypothesis (there is no difference between populations) is true then the observed difference between populations is just another value for the randomization distribution (Manly, 1997, p. 7).
Jean-Pierre Rossi, <jean-pierre.rossi@supagro.inra.fr>
Manly, B.F.J. (1997). Randomization and Monte Carlo methods in biology. Chapman & Hall.
1 2 3 4 5 |
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.