How do I plot the mean instead of the median with geom_boxplot? [duplicate]

问题:

This question already has an answer here:

• Use mean in ggplot boxplots instead of median 1 answer
• How to plot mean and standard error in Boxplot in R 2 answers
• Changing whisker definition in geom_boxplot 3 answers

for some inane reason, I need to create a boxplot where the middle line is the mean instead of the median. I checked stackoverflow already and found examples of adding a mean line, but not exactly what I need. I tried using stat_smooth but no dice. Any ideas?

code below:

dust <- c(4.5, 3.7, 5, 5.2, 8.5, 6.6, 4.7, 5, 5.7, 4.3, 2.3, 7.6, 5.2,            6, 8.7, 7.5, 7.7, 11, 9, 6.5, 8.7, 5, 2.2, 7.5, 7.5, 3.5)  wind <- c("Present", "Absent", "Absent", "Absent", "Absent", "Absent",    "Absent", "Absent", "Absent", "Present", "Absent", "Absent",    "Present", "Present", "Absent", "Absent", "Absent", "Absent",    "Absent", "Present", "Absent", "Present", "Absent", "Absent",    "Absent", "Present")  df <- data.frame(dust,wind)  plot <- ggplot(data=df,aes(x=wind,y=dust))+geom_boxplot()+stat_smooth()  plot 

回答1:

There are a few ways to do this:

1. Using middle

The easiest is to simply call:

plot <- ggplot(data = df, aes(y = dust, x = wind)) +          geom_boxplot(aes(middle = mean(dust)) 

2. Using fatten = NULL

You can also take advantage of the fatten parameter in geom_boxplot(). This controls the thickness of the median line. If we set it to NULL, then it will not plot a median line, and we can insert a line for the mean using stat_summary.

plot <- ggplot(data = df, aes(y = dust, x = wind)) +    geom_boxplot(fatten = NULL) +   stat_summary(fun.y = mean, geom = "errorbar", aes(ymax = ..y.., ymin = ..y..),                width = 0.75, size = 1, linetype = "solid") print(plot) 

Output using fatten = NULL

As you can see, the above method plots just fine, but when you evaluate the code it will output some warning messages because fatten is not really expected to take a NULL value.

The upside is that this method is possibly a bit more flexible, as we are essentially "erasing" the median line and adding in whatever we want. For example, we could also choose to keep the median, and add the mean as a dashed line.

回答2:

ggplot(df) +    geom_boxplot(     aes(       x = wind, ymin = min(dust), lower = quantile(dust, .25),        middle = mean(dust), upper = quantile(dust, .75),       ymax = max(dust)     ), stat = "identity"   ) 

文章来源: How do I plot the mean instead of the median with geom_boxplot? [duplicate]