title: How to add SE bars to bar-graph in R code?
body: <p>I'm new to R, and would like to add <strong>standard error</strong> bars to my bar-graph. I have the following code:</p>
  
  <pre><code>p1 &lt;- ggplot(plot1, aes(x=factor(drink_type), y=value, fill = manipulation)) + 
    stat_summary(fun.y="mean", geom="bar", position="dodge") +
    theme_classic() +
   labs(x = 'Drink type', y = 'Evidence accumulation')
  
  p1 + stat_summary(fun.data = mean_cl_normal, geom = "errorbar", width = .08, position = position_dodge(0.9)) 
  </code></pre>
  
  <p>However, I'm not sure whether this 'geom = "errorbar" produces the standard error bars (which is what I am after). This is the data I am working from. I wonder if I need to create a new column that is the SE of the 'value' column in order to present the standard error bars?</p>
  
  <pre><code>ppt | manipulation |   drink_type           |  value
  1   |       n      |   avg_alcohol_drift    |  1.8854094
  1   |       p      |   avg_alcohol_drift    |  1.6257274
  1   |       n      |   avg_softdrink_drift  |  1.8519074
  1   |       p      |   avg_softdrink_drift  |  1.8477995
  </code></pre>
  
  <p>Any help would be really appreciated! </p>