使用geom_smooth将glm拟合到分数 [英] Using geom_smooth for fitting a glm to fractions

问题描述

此帖子与这里有xy个分组数据，其中y是分数:

Here I have xy grouped data where y are fractions:

library(dplyr)
library(ggplot2)
library(ggpmisc)

set.seed(1)
df1 <- data.frame(value = c(0.8,0.5,0.4,0.2,0.5,0.6,0.5,0.48,0.52),
                 age = rep(c("d2","d4","d45"),3),
                 group = c("A","A","A","B","B","B","C","C","C")) %>%
  dplyr::mutate(time = as.integer(age)) %>%
  dplyr::arrange(group,time) %>%
  dplyr::mutate(group_age=paste0(group,"_",age))
df1$group_age <- factor(df1$group_age,levels=unique(df1$group_age))

我要实现的是将df1绘制为条形图，如下所示:

What I'm trying to achieve is to plot df1 as a bar plot, like this:

ggplot(df1,aes(x=group_age,y=value,fill=age)) +
  geom_bar(stat='identity')

但是我想将每个group一个binomial glm与一个logit link function匹配，以估计time对这些分数的影响.

But I want to fit to each group a binomial glm with a logit link function, which estimates how these fractions are affected by time.

比方说，每个group中的每个age(time)都有100个观测值:

Let's say I have 100 observations per each age (time) in each group:

df2 <- do.call(rbind,lapply(1:nrow(df1),function(i){
  data.frame(age=df1$age[i],group=df1$group[i],time=df1$time[i],group_age=df1$group_age[i],value=c(rep(T,100*df1$value[i]),rep(F,100*(1-df1$value[i]))))
}))

然后每个group(例如group A)的glm是:

Then the glm for each group (e.g., group A) is:

glm(value ~ time, dplyr::filter(df2, group == "A"), family = binomial(link='logit'))

所以我想将每个group的估计regression slopes以及它们对应的p-value s添加到图上(类似于我在此发布).

So I would like to add to the plot above the estimated regression slopes for each group along with their corresponding p-values (similar to what I'm doing for the continuous df$value in this post).

我认为使用:

ggplot(df1,aes(x=group_age,y=value,fill=age)) +
  geom_bar(stat='identity') +
  geom_smooth(data=df2,mapping=aes(x=group_age,y=value,group=group),color="black",method='glm',method.args=list(family=binomial(link='logit')),size=1,se=T) +
  stat_poly_eq(aes(label=stat(p.value.label)),formula=my_formula,parse=T,npcx="center",npcy="bottom") +
  scale_x_log10(name="Age",labels=levels(df$age),breaks=1:length(levels(df$age))) +
  facet_wrap(~group) + theme_minimal()

可以工作，但出现错误:

Would work but I get the error:

Error in Math.factor(x, base) : ‘log’ not meaningful for factors

有什么办法做对了吗?

推荐答案

我相信这会有所帮助:

library(tidyverse)
library(broom)

df2$value <- as.numeric(df2$value)

#Estimate coefs
dfmodel <- df2 %>% group_by(group) %>%
  do(fitmodel = glm(value ~ time, data = .,family = binomial(link='logit')))
#Extract coeffs
dfCoef = tidy(dfmodel, fitmodel)
#Create labels
dfCoef %>% filter(term=='(Intercept)') %>% mutate(Label=paste0(round(estimate,3),'(p=',round(p.value,3),')'),
                                                  group_age=paste0(group,'_','d4')) %>%
  select(c(group,Label,group_age)) -> Labels
#Values
df2 %>% group_by(group,group_age) %>% summarise(value=sum(value)) %>% ungroup() %>%
  group_by(group) %>% filter(value==max(value)) %>% select(-group_age) -> values
#Combine
Labels %>% left_join(values) -> Labels
Labels %>% mutate(age=NA) -> Labels
#Plot
ggplot(df2,aes(x=group_age,y=value,fill=age)) +
  geom_text(data=Labels,aes(x=group_age,y=value,label=Label),fontface='bold')+
  geom_bar(stat='identity')+
  facet_wrap(.~group,scales='free')

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