title: Compute probability of union of n events from array
body: <p>I have a PHP array containing N probabilities (of N different events). So it looks like:  </p>
  
  <pre><code>$events = [0.85, 1, 0, 0.15, 0.49, 1, 1, 0, 0, 0.59, 0.93]
  </code></pre>
  
  <p>where each value in the array is the probability of an event. I need to compute the probability of the union of those events. That is, how do I compute the probability of at least one event happening ?</p>