entropy.ChaoShen estimates the Shannon entropy H of the random variable Y
from the corresponding observed counts y using the method of Chao and Shen (2003).
the unit in which entropy is measured.
The default is "nats" (natural units). For
computing entropy in "bits" set unit="log2".
Details
The Chao-Shen entropy estimator (2003) is a Horvitz-Thompson (1952)
estimator applied to the problem of entropy estimation,
with additional coverage correction as proposed by Good (1953).
Note that the Chao-Shen estimator is not a plug-in estimator, hence there
are no explicit underlying bin frequencies.
Value
entropy.ChaoShen returns an estimate of the Shannon entropy.
Chao, A., and T.-J. Shen. 2003. Nonparametric estimation of Shannon's
index of diversity when there are unseen species in sample.
Environ. Ecol. Stat. 10:429-443.
Good, I. J. 1953. The population frequencies of species and the estimation of
population parameters. Biometrika 40:237-264.
Horvitz, D.G., and D. J. Thompson. 1952. A generalization of sampling without
replacement from a finite universe. J. Am. Stat. Assoc. 47:663-685.