="mi">1</span><span class="p">)</span>
<span class="n">data</span><span class="p">[</span><span class="s1">&#39;BILL_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_BILL_AMT</span><span class="p">]</span><span class="o">.</span><span class="n">apply</span><span class="p">(</span>
    <span class="k">lambda</span> <span class="n">x</span><span class="p">:</span> <span class="n">np</span><span class="o">.</span><sp