condition mean min max ZT0-3 6.6499999999999995 6.6499999999999995 6.6499999999999995 ZT4-7 1.9 1.9 1.9 ZT8-11 1.7 1.7 1.7 ZT12-15 5.25 5.25 5.25 ZT16-19 6.9 6.9 6.9 ZT20-23 1.8 1.8 1.8