condition mean min max ZT0-3 2.611385 2.30734 2.9154299999999997 ZT4-7 3.450955 3.450955 3.450955 ZT8-11 2.68586 2.68586 2.68586 ZT12-15 0 0 0 ZT16-19 4.086385 4.086385 4.086385 ZT20-23 4.740485 4.740485 4.740485