title: Grouped Bar Plot + SD from imported excel data
body: <p>I've recently been trying to convert to R from Excel, and have been struggling a bit. </p>
  
  <p>My goal right now is to create a grouped bar plot of the means of 2 groups: Pre-Contrast and Post-Contrast.</p>
  
  <p>Each should have "Control" and "Treated" groups.</p>
  
  <p>I'm not sure how to make my data reproducible (would I upload the excel sheet?)</p>
  
  <p><a href="https://i.stack.imgur.com/uIUrb.png" rel="nofollow noreferrer">Data Sheet</a></p>
  
  <p><a href="https://i.stack.imgur.com/kJgxj.png" rel="nofollow noreferrer">This is the graph I'm trying to produce</a></p>
  
  <pre><code>    library(plyr)
      library(tidyverse)
      library(readxl)
  
      t2&lt;- read_excel("t2quant.xlsx")
      summary(t2)
      colwise(sd)(t2)
  </code></pre>
  
  <p>Copy and paste from dput(t2):</p>
  
  <pre><code>structure(list(Pre_Contrast_Control = c(14, 10.4, 11), Pre_Contrast_Treated = c(16.7, 
      15, 12), Post_Contrast_Control = c(6, 5.8, 6.5), Post_Contrast_Treated = c(3.5, 
      3.7, 2.6)), .Names = c("Pre_Contrast_Control", "Pre_Contrast_Treated", 
      "Post_Contrast_Control", "Post_Contrast_Treated"), class = c("tbl_df", 
      "tbl", "data.frame"), row.names = c(NA, -3L))
  </code></pre>
  
  <p>I used colwise to obtain the SD of the values in  each column.
  How would I go about making grouped bar plots of the mean +/- the SD of each column?</p>
  
  <p>I would really appreciate the help, everyone.</p>