air_counts_permuted_means</span><span class="p">)</span> <span class="o">/</span> <span class="n">pair_counts_permuted_stds</span>
    <span class="n">z_scores</span><span class="p">[</span><span class="n">z_scores</span> <span class="o">&lt;</span> <span class="mi">0</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
    <span class="n">z_score_df</span> <span class="o">=</span> <span class="n">pd</span><span class="o">.</span><span class="n">DataFrame</span><span class="p">(