condition mean min max ZT0-3 5.550000000000001 5.550000000000001 5.550000000000001 ZT4-7 2.1 2.1 2.1 ZT8-11 4.75 4.75 4.75 ZT12-15 6.55 6.55 6.55 ZT16-19 6.3 6.3 6.3 ZT20-23 3.8 3.8 3.8