condition mean min max ZT0-3 7.949999999999999 7.949999999999999 7.949999999999999 ZT4-7 8.4 8.4 8.4 ZT8-11 2.6 2.6 2.6 ZT12-15 4.45 4.45 4.45 ZT16-19 3.6 3.6 3.6 ZT20-23 3.35 3.35 3.35