condition mean min max ZT0-3 5.699999999999999 5.699999999999999 5.699999999999999 ZT4-7 6.7 6.7 6.7 ZT8-11 7.35 7.35 7.35 ZT12-15 7.5 7.5 7.5 ZT16-19 9.45 9.45 9.45 ZT20-23 20.200000000000003 20.200000000000003 20.200000000000003