propodds(VGAM)
propodds()所属R语言包：VGAM
Proportional Odds Model for Ordinal Regression
比例优势模型为序回归
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Fits the proportional odds model to a (preferably ordered) factor response.
适合的比例优势模型（最好是订购）因子反应。
用法----------Usage----------
propodds(reverse = TRUE, whitespace = FALSE)
参数----------Arguments----------
参数：reverse, whitespace
Logical. Fed into arguments of the same name in cumulative.
逻辑。送入的参数相同名称的cumulative。
Details
详细信息----------Details----------
The proportional odds model is a special case from the class of cumulative link models. It involves a logit link applied to cumulative probabilities and a strong parallelism assumption. A parallelism assumption means there is less chance of numerical problems because the fitted probabilities will remain between 0 and 1; however the parallelism assumption ought to be checked, e.g., via a likelihood ratio test. This VGAM family function is merely a shortcut for cumulative(reverse = reverse, link = "logit", parallel = TRUE). Please see cumulative for more details on this model.
比例的的赔率模型是一个特殊的情况下，链路累积模型之类的。它涉及到的累积概率和强大的并行假设一个logit的关联。甲并行假定意味着有数值问题的机会少，因为拟合的概率将保持在0和1之间，然而的并行假设应该进行检查，例如，通过似然比检验。这VGAM家庭功能仅仅是一个快捷方式cumulative(reverse = reverse, link = "logit", parallel = TRUE)。请看到cumulative这种模式的详细信息。
值----------Value----------
An object of class "vglmff" (see vglmff-class). The object is used by modelling functions such as vglm, and vgam.
类的一个对象"vglmff"（见vglmff-class）。该对象被用于建模功能，如vglm，vgam。
警告----------Warning ----------
No check is made to verify that the response is ordinal; see ordered.
不进行任何检查来验证的响应顺序; ordered。
（作者）----------Author(s)----------
Thomas W. Yee
参考文献----------References----------
Analysis of Ordinal Categorical Data, 2nd ed. New York: Wiley.
The <code>VGAM</code> package for categorical data analysis. Journal of Statistical Software, 32, 1–34. http://www.jstatsoft.org/v32/i10/.
Vector generalized additive models. Journal of the Royal Statistical Society, Series B, Methodological, 58, 481–493.
http://www.stat.auckland.ac.nz/~yee contains further information and examples.
参见----------See Also----------
cumulative.
cumulative。
实例----------Examples----------
# Fit the proportional odds model, p.179, in McCullagh and Nelder (1989)[适合的比例优势模型，第179页，McCullagh和Nelder（1989）]
pneumo = transform(pneumo, let = log(exposure.time))
(fit = vglm(cbind(normal, mild, severe) ~ let, propodds, pneumo))
depvar(fit) # Sample proportions[样本比例]
weights(fit, type = "prior") # Number of observations[若干意见]
coef(fit, matrix = TRUE)
constraints(fit) # Constraint matrices[约束矩阵]
summary(fit)
# Check that the model is linear in let ----------------------[检查，该模型是线性的，让----------------------]
fit2 = vgam(cbind(normal, mild, severe) ~ s(let, df = 2), propodds, pneumo)
## Not run: plot(fit2, se = TRUE, lcol = 2, scol = 2) [＃不运行图（FIT2，SE = TRUE，LCOL = 2，SCOL = 2）]
# Check the proportional odds assumption with a LRT ----------[检查的比例赔率假设与轻铁----------]
(fit3 = vglm(cbind(normal, mild, severe) ~ let,
cumulative(parallel = FALSE, reverse = TRUE), pneumo))
pchisq(deviance(fit) - deviance(fit3),
df = df.residual(fit) - df.residual(fit3), lower.tail = FALSE)
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-10-1 15:49:38
