<?php

$numers = array(
  array(198,208,109,11,636),
  array(198,188,84,55,756),
  array(194,206,113,13,531),
  array(184,213,127,18,101),
  array(194,213,127,23,110),
  array(984,213,127,44,125),
  array(184,213,127,88,980),
  array(995,211,129,63,888)
);

$num_cols = count($numers[0]);

for ($i = 0; $i < $num_cols; $i++) {
  $column = array_column($numers, $i); 
  $average = array_sum($column) / count($column);
  echo "Column $i average: $average<br>";
}

输出：

Column 0 average: 391.375
Column 1 average: 208.125
Column 2 average: 117.875
Column 3 average: 39.375
Column 4 average: 515.875