title: confidence interval error bars for ggplot
body: <p>I want to put confidence interval error bars for ggplot.</p>
  
  <p>I have a dataset and I am plotting it with ggplot as:</p>
  
  <pre><code>df &lt;- data.frame(
          Sample=c("Sample1", "Sample2", "Sample3", "Sample4", "Sample5"), 
          Weight=c(10.5, NA, 4.9, 7.8, 6.9))
  
  p &lt;- ggplot(data=df, aes(x=Sample, y=Weight)) + 
  geom_bar(stat="identity", fill="black") + 
  scale_y_continuous(expand = c(0,0), limits = c(0, 8)) + 
  theme_classic() + 
  theme(axis.text.x = element_text(angle = 45, hjust = 1)
  
  p
  </code></pre>
  
  <p>I am new to adding error bars. I looked at some options using geom_bar but I could not make it work.</p>
  
  <p>I will appreciate any help to put confidence interval error bars in the barplot. Thank you!</p>