condition mean min max ZT0-3 18.3 18.3 18.3 ZT4-7 7.7 7.7 7.7 ZT8-11 10.45 10.45 10.45 ZT12-15 15.15 15.15 15.15 ZT16-19 4.6 4.6 4.6 ZT20-23 6.699999999999999 6.699999999999999 6.699999999999999