Boxplot show the value of mean

Question

In this boxplot we can see the mean but how can we have also the number value on the plot for every mean of every box plot    ggplot data PlantGrowth  aes x group  y weight  fill group     geom boxplot          stat summary fun y mean  colour  darkred   geom  point                               shape 18  size 3 show guide   FALSE

User · Accepted Answer

First  you can calculate the group means with aggregate   means  lt - aggregate weight    group  PlantGrowth  mean    This dataset can be used with geom text   library ggplot2  ggplot data PlantGrowth  aes x group  y weight  fill group     geom boxplot       stat summary fun y mean  colour  darkred   geom  point                   shape 18  size 3 show guide   FALSE       geom text data   means  aes label   weight  y   weight   0 08     Here    0 08 is used to place the label above the point representing the mean       An alternative version without ggplot2   means  lt - aggregate weight    group  PlantGrowth  mean   boxplot weight   group  PlantGrowth  points 1 3  means weight  col    red   text 1 3  means weight   0 08  labels   means weight

User · Answer

You can also use a function within stat summary to calculate the mean and the hjust argument to place the text  you need a additional function but no additional data frame   fun mean  lt - function x     return data frame y mean x  label mean x na rm T       ggplot PlantGrowth aes x group y weight     geom boxplot aes fill group     stat summary fun y   mean  geom  point  colour  darkred   size 3    stat summary fun data   fun mean  geom  text   vjust -0 7

User · Answer

You can use the output value from stat summary    ggplot data PlantGrowth  aes x group  y weight  fill group      geom boxplot      stat summary fun y mean  colour  darkred   geom  point   hape 18  size 3 show guide   FALSE    stat summary fun y mean  colour  red   geom  text   show guide   FALSE                  vjust -0 7  aes  label round   y    digits 1

User · Answer

The Magrittr way I know there is an accepted answer already  but I wanted to show one cool way to do it in single command with the help of magrittr package  PlantGrowth       open dataset and make colnames accessible with     split weight group   T gt     split by group and side-pipe it into boxplot boxplot   gt     plot lapply mean    gt     data from split can still be used thanks to side-pipe   T gt    unlist  T gt     convert to atomic and side-pipe it to points points pch 18     gt     add points for means to the boxplot text x   0 06 labels      use the values to print text  This code will produce a boxplot with means printed as points and values   I split the command on multiple lines so I can comment on what each part does  but it can also be entered as a oneliner  You can learn more about this in my gist

[r] Boxplot show the value of mean

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