title: Test for coplanar points, and comparing best planar fit of many sets of points?
body: <p>Perhaps best asked in three parts:</p>
  <ol>
  <li><p>Given five not necessarily coplanar points (in 3 dimensions), what is a good measure of how close to coplanar they are?</p>
  </li>
  <li><p>Given another set of five not necessarily coplanar points, how can we assess which of these two sets of five points is “more coplanar”?</p>
  </li>
  <li><p>Given n sets of five not necessarily coplanar points, how can we order these sets of points from “most coplanar” to “least coplanar”?</p>
  </li>
  </ol>
  <p>Suggestions?</p>
  <p>I’m working with sets of five points at a time, but will eventually need to consider more points in these sets.</p>
  <p>Is this a well-formulated question? An algorithm would be helpful, especially if coded in Python.</p>