title: Simple trend analysis algorithm
body: <p>OK, so you have some historic data in the form of [say] an array of integers.  This, for example, could represent free-space on a server HDD over a two-year period, with each array element representing a daily sample.</p>
  
  <p>The data (free-space in this example) has a downward trend, but also has periodic positive spikes where files have been removed/compressed, Etc.</p>
  
  <p>How would you go about identifying the overall trend for the two-year period, i.e.: iron out the peaks and troughs in the data?</p>
  
  <p>Now, I did A-level statistics and then a stats module in my degree, but I've slept over 7,000 times since then, and well, it's leaked out of my brain.</p>
  
  <p>I'm not after a bit of code as such, more of a description of how you'd approach this problem...</p>
  
  <p>Thanks in advance!</p>