title: How to do a one tail pvalue calculate in Python?
body: <p>I have two arrays, one is an array of corrected values, x, and the other is an array of the original values(before a correction was applied), y. I know that if I want to do a two-tailed ttest to get the two-tailed pvalue I need to do this:</p>
  
  <pre><code>t_statistic, pvlaue = scipy.stats.ttest_ind(x, y, nan_policy='omit')
  </code></pre>
  
  <p>However this only tells me if the two arrays are significantly different from eachother. I want to show that the corrected values, x, are significantly less than y. To do this it seems like I need to get the one-tailed pvalue but I can't seem to find a function that does this. Any ideas?</p>