condition mean min max ZT0-3 3.37739 3.37739 3.37739 ZT4-7 2.00512 2.00512 2.00512 ZT8-11 3.05685 3.05685 3.05685 ZT12-15 2.930935 2.930935 2.930935 ZT16-19 5.432525 5.432525 5.432525 ZT20-23 3.6894 3.6894 3.6894