title: Adjust boxplot arm width, and add horizontal lines to the bottom and top
body: <p>I have created an image with ggplot2. Code is listed below:</p>
  
  <pre><code>ggplot(aes(y = SCORE, x = DATE, fill = CATEGORY), data = data_R1000) 
  + geom_boxplot(width=0.6,position = position_dodge(width = 0.75),outlier.size = 0, size = 0.5)
  + ylim(20,100) + labs(title = "US_MARKETOR") + theme(legend.position="bottom") 
  + theme(panel.background = element_rect(fill = "transparent",colour = NA)) 
  + theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank()) 
  + scale_fill_hue(c=50, l=85)
  </code></pre>
  
  <p>the result looks like below<img src="https://i.stack.imgur.com/Ch70b.png" alt="enter image description here"></p>
  
  <p>now, i will have to make the arm of box plots thicker, that is, the vertical lines above and beneath the bar. I have tried adjust the 'size = 2', but this gives me a thicker line for the entire box plot.</p>
  
  <p><img src="https://i.stack.imgur.com/W6EIq.png" alt="enter image description here"></p>
  
  <p>this is definitely not what I want, and I am having trouble in making only the arm part thicker. Please let me know if there is a way I can do this. </p>
  
  <p>***in addition, if there is no way to do this, how can I add a horizontal line and the top and bottom of the arms? (Just like the normal box plot generated without using ggplot2)</p>
  
  <p>Thank you very much!!!</p>