condition mean min max ZT0-3 7.07791 7.07791 7.07791 ZT4-7 7.643107 7.643107 7.643107 ZT8-11 8.499241000000001 8.499241000000001 8.499241000000001 ZT12-15 8.150219499999999 8.150219499999999 8.150219499999999 ZT16-19 7.8979865 7.8979865 7.8979865 ZT20-23 8.219479 8.219479 8.219479