ult: another interpretation of the result, is that it
          finds the number of trials (success+failures) that will lead to an <span class="emphasis"><em>alpha</em></span>
          probability of observing k failures or fewer.
        </p>
<h6>
<a name="math_toolkit.dist_ref.dists.negative_binomial_dist.h7"></a>
          <span class="phrase"><a name="math_toolkit.dist_ref.dists.negative_binomial_dist.estimating_number_of_trials_to_0"></a></span><a class="link" href="negative_binomial_dist.html#math_to