condition mean min max ZT0-3 1.838695 1.838695 1.838695 ZT4-7 4.45725 4.45725 4.45725 ZT8-11 2.23646 2.23646 2.23646 ZT12-15 2.016105 2.016105 2.016105 ZT16-19 3.388395 3.388395 3.388395 ZT20-23 2.116845 2.116845 2.116845