</span> <span class="o">=</span> <span class="n">data</span><span class="p">[</span><span class="n">old_PAY</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><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