annotate grouped boxplot in ggplot - add number of observations below boxplot - r

Question

I want to add the number of observations below each boxplot (as in the figure- no need for the red square). :)
However, I don't know how to annotate this type of boxplot (see figure below).multiple boxplot annotate number of observations
Does anyone know how to do it?
This is the code that I used to plot this figure.
ggplot(data=MIOT1, aes(stage, time, fill=resp)) +
geom_boxplot(color= "black", lwd=0.3) +
stat_summary(fun.y=mean, geom="point", shape=0, size=1, colour="black", position=position_dodge(width=0.75)) +
scale_fill_manual(values=c("grey25", "grey50", "grey67")) +
annotation_custom(mygrobA) +
scale_y_continuous(limits=c(-10,124)) +
theme(panel.grid.major = element_blank(),
panel.grid.minor = element_blank(),
strip.background = element_rect(colour="black"),
panel.border = element_rect(colour = "black", fill="transparent")) +
xlab(bquote(' ')) +
ylab(bquote('Minimum Consecutive Time (s)')) +
labs(title="SATIATION\n") +
theme(axis.title.y = element_text(colour="black",size=10,face="bold"),
axis.text.x = element_text(colour="black",size=8, face="plain"),
axis.text.y = element_text(colour="black",size=8, face="plain"),
axis.title.x = element_text(colour="black",size=10,face="bold")) +
theme(panel.background = element_rect(fill = "white")) +
theme(plot.title = element_text(lineheight=.8, size=10, face="bold")) +
theme(legend.title=element_blank(), legend.key = element_rect(fill = NA, colour = NA)) +
theme(legend.position="none") +
theme(legend.background = element_rect(fill=NA)) +
theme(plot.margin = unit(c(.25,.25,.0,.0), "cm"))<i>
EXAMPLE DATA
MIOT1 is a numeric variable (y-axis), and I am considering two grouping factors (development stage- x axis) and the response (unresponsive, coastal, lagoon).
Something like
stage resp time
pre U 100
pre U 80
pre U 50
pre C 20
flex U 80
flex U 90
flex C 10
flex C 20
post U 40
post U 30
post U 60
post C 80
post C 100
post L 50
post L 40
Thank you!
Pedro

Answer 1

Here's a simple example of how to do it, using the built-in mtcars data frame:
ggplot(mtcars, aes(factor(cyl), mpg)) +
geom_boxplot() +
geom_text(stat="count", aes(label=..count..), y=min(mtcars$mpg)- 0.6)
In your case, it will be something like
ggplot(data=MIOT1, aes(stage, time, fill=resp)) +
geom_boxplot(color= "black", lwd=0.3) +
geom_text(stat="count", aes(label=..count..), y=min(MIOT1$time))
where you may have to adjust the y location of the text labels and you might also need to adjust the range of the y-axis to make room for the labels.
UPDATE: I was able to reproduce the error you reported, but I'm not sure how to fix it. Instead, you can pre-summarize the data and then add it to the plot. Here's an example:
library(dplyr)
# Get counts by desired grouping variables
counts = mtcars %>% group_by(cyl, am) %>% tally
ggplot(mtcars, aes(factor(cyl), mpg, fill=factor(am))) +
geom_boxplot(position=position_dodge(0.9)) +
geom_text(data=counts, aes(label=n, y=min(mtcars$mpg) - 0.6),
position=position_dodge(0.9))

Answer 2

IN SUMMARY EIPI10 ANSWERED MY QUESTION:
library(dplyr)
# Get counts by desired grouping variables
counts = mtcars %>% group_by(cyl, am) %>% tally
ggplot(mtcars, aes(factor(cyl), mpg, fill=factor(am))) +
geom_boxplot(position=position_dodge(0.9)) +
geom_text(data=counts, aes(label=n, y=min(mtcars$mpg) - 0.6), position=position_dodge(0.9)