Distribution.df: Data Frame Summarizing Available Probability Distributions and
Estimation Methods
Description
Data frame summarizing information about available probability
distributions in Rand the EnvStats package, and which
distributions have associated functions for estimating distribution
parameters.source
The EnvStats package.Details
The table below summarizes the probability distributions available in
Rand EnvStats. For each distribution, there are four
associated functions for computing density values, percentiles, quantiles,
and random numbers. The form of the names of these functions are
d
abb, p
abb, q
abb, and
r
abb, where abb is the abbreviated name of the
distribution (see table below). These functions are described in the
help file with the name of the distribution (see the first column of the
table below). For example, the help file for Beta describes the
behavior of dbeta
, pbeta
, qbeta
,
and rbeta
.
For most distributions, there is also an associated function for
estimating the distribution parameters, and the form of the names of
these functions is e
abb, where abb is the
abbreviated name of the distribution (see table below). All of these
functions are listed in the help file
Estimating Distribution Parameters. For example,
the function ebeta
estimates the shape parameters of a
Beta distribution based on a random sample of observations from
this distribution.
For some distributions, there are functions to estimate distribution
parameters based on Type I censored data. The form of the names of
these functions is e
abbSinglyCensored
for
singly censored data and e
abbMultiplyCensored
for
multiply censored data. All of these functions are listed under the heading
Estimating Distribution Parameters in the help file
Censored Data.
Table 1a. Available Distributions: Name, Abbreviation, Type, and Range
llll{
Name Abbreviation Type Range
Beta beta
Continuous $[0, 1]$
Binomial binom
Finite $[0, size]$
Discrete (integer)
Cauchy cauchy
Continuous $(-\infty, \infty)$
Chi chi
Continuous $[0, \infty)$
Chi-square chisq
Continuous $[0, \infty)$
Exponential exp
Continuous $[0, \infty)$
Extreme evd
Continuous $(-\infty, \infty)$
Value
F f
Continuous $[0, \infty)$
Gamma gamma
Continuous $[0, \infty)$
Gamma gammaAlt
Continuous $[0, \infty)$
(Alternative)
Generalized gevd
Continuous $(-\infty, \infty)$
Extreme for $shape = 0$
Value
$(-\infty, location + \frac{scale}{shape}]$
for $shape > 0$
$[location + \frac{scale}{shape}, \infty)$
for $shape < 0$
Geometric geom
Discrete $[0, \infty)$
(integer)
Hypergeometric hyper
Finite $[0, min(k,m)]$
Discrete (integer)
Logistic logis
Continuous $(-\infty, \infty)$
Lognormal lnorm
Continuous $[0, \infty)$
Lognormal lnormAlt
Continuous $[0, \infty)$
(Alternative)
Lognormal lnormMix
Continuous $[0, \infty)$
Mixture
Lognormal lnormMixAlt
Continuous $[0, \infty)$
Mixture
(Alternative)
Three- lnorm3
Continuous $[threshold, \infty)$
Parameter
Lognormal
Truncated lnormTrunc
Continuous $[min, max]$
Lognormal
Truncated lnormTruncAlt
Continuous $[min, max]$
Lognormal
(Alternative)
Negative nbinom
Discrete $[0, \infty)$
Binomial (integer)
Normal norm
Continuous $(-\infty, \infty)$
Normal normMix
Continuous $(-\infty, \infty)$
Mixture
Truncated normTrunc
Continuous $[min, max]$
Normal
Pareto pareto
Continuous $[location, \infty)$
Poisson pois
Discrete $[0, \infty)$
(integer)
Student's t t
Continuous $(-\infty, \infty)$
Triangular tri
Continuous $[min, max]$
Uniform unif
Continuous $[min, max]$
Weibull weibull
Continuous $[0, \infty)$
Wilcoxon wilcox
Finite $[0, m n]$
Rank Sum Discrete (integer)
Zero-Modified zmlnorm
Mixed $[0, \infty)$
Lognormal
(Delta)
Zero-Modified zmlnormAlt
Mixed $[0, \infty)$
Lognormal
(Delta)
(Alternative)
Zero-Modified zmnorm
Mixed $(-\infty, \infty)$
Normal
}
Table 1b. Available Distributions: Name, Parameters, Parameter Default Values, Parameter Ranges, Estimation Method(s)
lllll{
Default Parameter Estimation
Name Parameter(s) Value(s) Range(s) Method(s)
Beta shape1
$(0, \infty)$ mle, mme, mmue
shape2
$(0, \infty)$
ncp
0
$(0, \infty)$
Binomial size
$[0, \infty)$ mle/mme/mvue
prob
$[0, 1]$
Cauchy location
0
$(-\infty, \infty)$
scale
1
$(0, \infty)$
Chi df
$(0, \infty)$
Chi-square df
$(0, \infty)$
ncp
0
$(-\infty, \infty)$
Exponential rate
1
$(0, \infty)$ mle/mme
Extreme location
0
$(-\infty, \infty)$ mle, mme, mmue, pwme
Value scale
1
$(0, \infty)$
F df1
$(0, \infty)$
df2
$(0, \infty)$
ncp
0
$(0, \infty)$
Gamma shape
$(0, \infty)$ mle, bcmle, mme, mmue
scale
1
$(0, \infty)$
Gamma mean
$(0, \infty)$ mle, bcmle, mme, mmue
(Alternative) cv
1
$(0, \infty)$
Generalized location
0
$(-\infty, \infty)$ mle, pwme, tsoe
Extreme scale
1
$(0, \infty)$
Value shape
0
$(-\infty, \infty)$
Geometric prob
$(0, 1)$ mle/mme, mvue
Hypergeometric m
$[0, \infty)$ mle, mvue
n
$[0, \infty)$
k
$[1, m+n]$
Logistic location
0
$(-\infty, \infty)$ mle, mme, mmue
scale
1
$(0, \infty)$
Lognormal meanlog
0
$(-\infty, \infty)$ mle/mme, mvue
sdlog
1
$(0, \infty)$
Lognormal mean
exp(1/2)
$(0, \infty)$ mle, mme, mmue,
(Alternative) cv
sqrt(exp(1)-1)
$(0, \infty)$ mvue, qmle
Lognormal meanlog1
0
$(-\infty, \infty)$
Mixture sdlog1
1
$(0, \infty)$
meanlog2
0
$(-\infty, \infty)$
sdlog2
1
$(0, \infty)$
p.mix
0.5
$[0, 1]$
Lognormal mean1
exp(1/2)
$(0, \infty)$
Mixture cv1
sqrt(exp(1)-1)
$(0, \infty)$
(Alternative) mean2
exp(1/2)
$(0, \infty)$
cv2
sqrt(exp(1)-1)
$(0, \infty)$
p.mix
0.5
$[0, 1]$
Three- meanlog
0
$(-\infty, \infty)$ lmle, mme,
Parameter sdlog
1
$(0, \infty)$ mmue, mmme,
Lognormal threshold
0
$(-\infty, \infty)$ royston.skew,
zero.skew
Truncated meanlog
0
$(-\infty, \infty)$
Lognormal sdlog
1
$(0, \infty)$
min
0
$[0, max)$
max
Inf
$(min, \infty)$
Truncated mean
exp(1/2)
$(0, \infty)$
Lognormal cv
sqrt(exp(1)-1)
$(0, \infty)$
(Alternative) min
0
$[0, max)$
max
Inf
$(min, \infty)$
Negative size
$[1, \infty)$ mle/mme, mvue
Binomial prob
$(0, 1]$
mu
$(0, \infty)$
Normal mean
0
$(-\infty, \infty)$ mle/mme, mvue
sd
1
$(0, \infty)$
Normal mean1
0
$(-\infty, \infty)$
Mixture sd1
1
$(0, \infty)$
mean2
0
$(-\infty, \infty)$
sd2
1
$(0, \infty)$
p.mix
0.5
$[0, 1]$
Truncated mean
0
$(-\infty, \infty)$
Normal sd
1
$(0, \infty)$
min
-Inf
$(-\infty, max)$
max
Inf
$(min, \infty)$
Pareto location
$(0, \infty)$ lse, mle
shape
1
$(0, \infty)$
Poisson lambda
$(0, \infty)$ mle/mme/mvue
Student's t df
$(0, \infty)$
ncp
0
$(-\infty, \infty)$
Triangular min
0
$(-\infty, max)$
max
1
$(min, \infty)$
mode
0.5
$(min, max)$
Uniform min
0
$(-\infty, max)$ mle, mme, mmue
max
1
$(min, \infty)$
Weibull shape
$(0, \infty)$ mle, mme, mmue
scale
1
$(0, \infty)$
Wilcoxon m
$[1, \infty)$
Rank Sum n
$[1, \infty)$
Zero-Modified meanlog
0
$(-\infty, \infty)$ mvue
Lognormal sdlog
1
$(0, \infty)$
(Delta) p.zero
0.5
$[0, 1]$
Zero-Modified mean
exp(1/2)
$(0, \infty)$ mvue
Lognormal cv
sqrt(exp(1)-1)
$(0, \infty)$
(Delta) p.zero
0.5
$[0, 1]$
(Alternative)
Zero-Modified mean
0
$(-\infty, \infty)$ mvue
Normal sd
1
$(0, \infty)$
p.zero
0.5
$[0, 1]$
}References
Millard, S.P. (2013). EnvStats: An R Package for Environmental Statistics.
Springer, New York.