Bin      Observed   Expected   (O-E)²/E
 |Z| ≤ 1     6300       4778.8     484.2
 1<|Z|≤2      616       1902.7     870.1
 2<|Z|≤3       77        299.6     165.4
 3 < |Z|        7         18.9       7.5

 Total       7000         7000    1527.2