r - 调用 aictab 时未定义函数

Question

我在尝试生成 aictab 表时收到错误消息

代码

library(MASS)
library(AICcmodavg)

set.seed(456)
d <- data.frame(ID = 1:20,
                Ct = c(sample(x = 1:50, size = 12, replace = T), rep(x = 0, length.out = 8)),
                V = as.factor(rep(x = c("Dry", "Wet"), each = 2)),
                S = as.factor(rep(x = c("Sand", "Clay"), each = 2)))

m1 <- glm.nb(Ct ~ 1, data = d)
m2 <- glm.nb(Ct ~ V, data = d)
m3 <- glm.nb(Ct ~ S, data = d)

all_ms <- list(m1, m2, m3)
names(all_ms) <- c("null", "type", "soil")

aic_tb <- aictab(cand.set = all_ms, second.ord = TRUE)

输出

Error in aictab.default(cand.set = all_ms, second.ord = TRUE): Function not yet defined for this object class

谁能看出为什么会失败？

Answer 1

问题是 aictab() 似乎无法处理类 negbin 的对象(glm.nb() 的结果)。

一个简单的解决方法是使用 glm.convert() 修改您的输出，使其看起来像来自 glm() 的具有负二项式族的输出:

all_ms_glm <- lapply(all_ms, glm.convert)
aictab(cand.set = all_ms_glm, second.ord = TRUE)
# Model selection based on AICc:
#  
#      K   AICc Delta_AICc AICcWt Cum.Wt      LL
# null 2 396.34       0.00   0.35   0.35 -195.82
# soil 3 396.46       0.13   0.33   0.67 -194.48
# type 3 396.46       0.13   0.33   1.00 -194.48