title: Compute mean and standard deviation by group for multiple variables in a data.frame
body: <p><strong>Edit</strong> -- This question was originally titled &lt;&lt; Long to wide data reshaping in R >></p>
  
  <hr>
  
  <p>I'm just learning R and trying to find ways to apply it to help out others in my life. As a test case, I'm working on reshaping some data, and I'm having trouble following the examples I've found online. What I'm starting with looks like this:</p>
  
  <pre><code>ID  Obs 1   Obs 2   Obs 3
  1   43      48      37
  1   27      29      22
  1   36      32      40
  2   33      38      36
  2   29      32      27
  2   32      31      35
  2   25      28      24
  3   45      47      42
  3   38      40      36
  </code></pre>
  
  <p>And what I want to end up with will look like this:</p>
  
  <pre><code>ID  Obs 1 mean  Obs 1 std dev   Obs 2 mean  Obs 2 std dev
  1   x           x               x           x
  2   x           x               x           x
  3   x           x               x           x
  </code></pre>
  
  <p>And so forth. What I'm unsure of is whether I need additional information in my long-form data, or what. I imagine that the math part (finding the mean and standard deviations) will be the easy part, but I haven't been able to find a way that seems to work to reshape the data correctly to start in on that process.</p>
  
  <p>Thanks very much for any help.</p>