<span class="n">mean</span><span class="p">(</span><span class="n">x</span><span class="p">),</span> <span class="n">axis</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span>
<span class="n">data</span><span class="p">[</span><span class="s1">&#39;PAY_AMT_old_std&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="n">data</span><span class="p">[</span><span class="n">old_PAY_AMT</span><span class="p">]</span><span class="o">.</span><span class="n">apply</span