condition mean min max ZT0-3 6.550000000000001 6.550000000000001 6.550000000000001 ZT4-7 16.4 16.4 16.4 ZT8-11 6.1 6.1 6.1 ZT12-15 2.55 2.55 2.55 ZT16-19 4.3 4.3 4.3 ZT20-23 20.150000000000002 20.150000000000002 20.150000000000002