condition mean min max ZT0-3 17.900000000000002 17.900000000000002 17.900000000000002 ZT4-7 4.4 4.4 4.4 ZT8-11 4.5 4.5 4.5 ZT12-15 7.05 7.05 7.05 ZT16-19 8.2 8.2 8.2 ZT20-23 2.05 2.05 2.05