condition mean min max ZT0-3 17.9 17.9 17.9 ZT4-7 5.8 5.8 5.8 ZT8-11 12.15 12.15 12.15 ZT12-15 15.100000000000001 15.100000000000001 15.100000000000001 ZT16-19 10.65 10.65 10.65 ZT20-23 3.1 3.1 3.1