Weibull(stats)
Weibull()所属R语言包:stats
The Weibull Distribution
Weibull分布
译者:生物统计家园网 机器人LoveR
描述----------Description----------
Density, distribution function, quantile function and random generation for the Weibull distribution with parameters shape and scale.
密度分布函数,分位数函数和随机生成的Weibull分布参数shape和scale。
用法----------Usage----------
dweibull(x, shape, scale = 1, log = FALSE)
pweibull(q, shape, scale = 1, lower.tail = TRUE, log.p = FALSE)
qweibull(p, shape, scale = 1, lower.tail = TRUE, log.p = FALSE)
rweibull(n, shape, scale = 1)
参数----------Arguments----------
参数:x, q
vector of quantiles.
位数的向量。
参数:p
vector of probabilities.
概率向量。
参数:n
number of observations. If length(n) > 1, the length is taken to be the number required.
观测数。如果length(n) > 1,长度是所需的数量。
参数:shape, scale
shape and scale parameters, the latter defaulting to 1.
形状和规模参数,后者默认为1。
参数:log, log.p
logical; if TRUE, probabilities p are given as log(p).
逻辑;如果为TRUE,概率P日志(P)。
参数:lower.tail
logical; if TRUE (default), probabilities are P[X ≤ x], otherwise, P[X > x].
逻辑;如果是TRUE(默认),概率P[X ≤ x],否则,“P[X > x]。
Details
详情----------Details----------
The Weibull distribution with shape parameter a and scale parameter b has density given by
威布尔与shape参数a和scale参数b的分布密度给予
for x > 0. The cumulative distribution function is F(x) = 1 - exp(- (x/b)^a) on x > 0, the mean is E(X) = b Γ(1 + 1/a), and the Var(X) = b^2 * (Γ(1 + 2/a) - (Γ(1 + 1/a))^2).
x > 0。累积分布函数是F(x) = 1 - exp(- (x/b)^a)x > 0,平均:E(X) = b Γ(1 + 1/a),Var(X) = b^2 * (Γ(1 + 2/a) - (Γ(1 + 1/a))^2)。
值----------Value----------
dweibull gives the density, pweibull gives the distribution function, qweibull gives the quantile function, and rweibull generates random deviates.
dweibull给人的密度,pweibull给出了分布函数,qweibull给人的分量功能,rweibull产生随机的偏离。
Invalid arguments will result in return value NaN, with a warning.
无效的参数将导致返回值NaN,一个警告。
注意----------Note----------
The cumulative hazard H(t) = - log(1 - F(t)) is -pweibull(t, a, b, lower = FALSE, log = TRUE) which is just H(t) = (t/b)^a.
累积危险H(t) = - log(1 - F(t))是:-pweibull(t, a, b, lower = FALSE, log = TRUE)只是H(t) = (t/b)^a。
源----------Source----------
[dpq]weibull are calculated directly from the definitions. rweibull uses inversion.
[dpq]weibull直接从定义计算。 rweibull使用反转。
参考文献----------References----------
Continuous Univariate Distributions, volume 1, chapter 21. Wiley, New York.
参见----------See Also----------
Distributions for other standard distributions, including the Exponential which is a special case of the Weibull distribution.
其他标准分布的分布,包括指数,这是一个特殊情况下的Weibull分布。
举例----------Examples----------
x <- c(0,rlnorm(50))
all.equal(dweibull(x, shape = 1), dexp(x))
all.equal(pweibull(x, shape = 1, scale = pi), pexp(x, rate = 1/pi))
## Cumulative hazard H():[#累积危险的H():]
all.equal(pweibull(x, 2.5, pi, lower.tail=FALSE, log.p=TRUE), -(x/pi)^2.5,
tol = 1e-15)
all.equal(qweibull(x/11, shape = 1, scale = pi), qexp(x/11, rate = 1/pi))
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注:
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