condition mean min max ZT0-3 14.25 14.25 14.25 ZT4-7 2.2 2.2 2.2 ZT8-11 4.800000000000001 4.800000000000001 4.800000000000001 ZT12-15 2.1 2.1 2.1 ZT16-19 11.75 11.75 11.75 ZT20-23 3.9 3.9 3.9