title: Scatter plot with error bars
body: <p>How can I generate the following plot in R? Points, shown in the plot are the averages, and their ranges correspond to minimal and maximal values.
  I have data in two files (below is an example). </p>
  
  <pre><code>x   y
  1   0.8773
  1   0.8722
  1   0.8816
  1   0.8834
  1   0.8759
  1   0.8890
  1   0.8727
  2   0.9047
  2   0.9062
  2   0.8998
  2   0.9044
  2   0.8960
  ..  ...
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/SMqIx.png" alt="enter image description here"></p>