我有一个二项式 glm
,其中包含一个存在/不存在的响应变量和一个具有9个级别的因子变量,如下所示:
data$y<-factor(data$y,levels=c(0,1),labels=c("absent","present"))
table(data$y,data$site_name)
Andulay Antulang Basak Dauin Poblacion District 1 Guinsuan Kookoo's Nest Lutoban Pier Lutoban South Malatapay Pier
absent 4 4 1 0 3 1 5 5 2
present 2 2 5 6 3 5 1 1 4
model <- glm(y~site_name,data=data,binomial)
仅为简洁起见,跳过模型推断和验证,我该如何在一个箱线图中绘制每个站点出现概率及其置信区间?我想要的是类似于在R中绘制预测概率和置信区间所示的内容,但我希望用箱线图展示它,因为我的回归变量site_name是一个具有9个级别的因子,而不是一个连续变量。
我认为可以按以下方式计算必要的值(但不确定正确性):
将模型系数转换为成功概率的函数:
calc_val <- function(x){return(round(1/(1+1/(exp(x))),3))}
基于模型的预测概率:
prob <- tapply(predict(model,type="response"),data$site_name,function(x){round(mean(x),3)})
means <- as.data.frame(prob)
预测概率的75%和95%置信区间:
ci <- cbind(confint(model,level=0.9),confint(model,level=0.5))
rownames(ci) <- gsub("site_name","",rownames(ci))
ci <- t(apply(ci,1,calc_val))
将所有内容整合到一张表格中
ci<-cbind(means,ci)
ci
prob 5 % 95 % 25 % 75 % Pr(>|z|) stderr
Andulay 0.333 0.091 0.663 0.214 0.469 0.42349216 0.192
Antulang 0.333 0.112 0.888 0.304 0.696 1.00000000 0.192
Basak 0.833 0.548 0.993 0.802 0.964 0.09916496 0.152
Dauin Poblacion District 1 1.000 0.000 NA 0.000 1.000 0.99097988 0.000
Guinsuan 0.500 0.223 0.940 0.474 0.819 0.56032414 0.204
Kookoo's Nest 0.833 0.548 0.993 0.802 0.964 0.09916496 0.152
Lutoban Pier 0.167 0.028 0.788 0.130 0.501 0.51171512 0.152
Lutoban South 0.167 0.028 0.788 0.130 0.501 0.51171512 0.152
Malatapay Pier 0.667 0.364 0.972 0.640 0.903 0.25767454 0.192
所以我的问题有两个:
- 概率和置信区间的计算是否正确?
- 如何在箱线图中绘制这个数据?
编辑 这是一些通过 dput
提供的样本数据(也修改了上面的表格以匹配数据):
# dput(data[c("y", "site_name")])
data <- structure(list(y = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 2L, 2L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 1L, 2L, 2L, 1L, 2L, 2L, 2L, 2L, 1L, 2L, 2L, 2L, 2L, 2L), .Label = c("absent", "present"), class = "factor"), site_name = structure(c(2L, 2L, 2L, 2L, 2L, 2L, 9L, 9L, 9L, 9L, 9L, 9L, 4L, 4L, 4L, 4L, 4L, 4L, 8L, 8L, 8L, 8L, 8L, 8L, 7L, 7L, 7L, 7L, 7L, 7L, 5L, 5L, 5L, 5L, 5L, 5L, 1L, 1L, 1L, 1L, 1L, 1L, 3L, 3L, 3L, 3L, 3L, 3L, 6L, 6L, 6L, 6L, 6L, 6L), .Label = c("Andulay", "Antulang", "Basak", "Dauin Poblacion District 1", "Guinsuan", "Kookoo's Nest", "Lutoban Pier", "Lutoban South", "Malatapay Pier"), class = "factor")), .Names = c("y", "site_name"), row.names = c(125L, 123L, 126L, 124L, 128L, 127L, 154L, 159L, 157L, 158L, 156L, 155L, 111L, 114L, 116L, 115L, 112L, 113L, 152L, 151L, 148L, 150L, 153L, 149L, 143L, 146L, 144L, 147L, 142L, 145L, 164L, 165L, 161L, 163L, 160L, 162L, 120L, 122L, 121L, 117L, 118L, 119L, 137L, 136L, 139L, 141L, 140L, 138L, 129L, 134L, 131L, 135L, 133L, 130L), class = "data.frame")
#
dput(data[c("y", "site_name")])
的结果吗?(希望其他人可以从你的问题中复制数据到他们的 R 会话中 - 在你发布的格式下无法做到这一点) - user20650