title: What does Tensorflow mean with 'positive_threshold_0.500000_mean'?
body: <p>Tensorflow's <a href="https://www.tensorflow.org/versions/r0.10/api_docs/python/contrib.learn.html#evaluate" rel="nofollow">evaluate function</a> spits out a bunch of stats: </p>
  
  <pre><code>accuracy: 0.915224
  accuracy/baseline_target_mean: 0.220896
  accuracy/threshold_0.500000_mean: 0.915224
  auc: 0.937926
  global_step: 200
  labels/actual_target_mean: 0.220896
  labels/prediction_mean: 0.203677
  loss: 0.247065
  precision/positive_threshold_0.500000_mean: 0.991379
  recall/positive_threshold_0.500000_mean: 0.621622
  </code></pre>
  
  <p>What do <code>baseline_target_mean</code> (after accuracy) and <code>positive_threshold_0.500000_mean</code> (after recall and precision) mean?</p>