condition mean min max ZT0-3 8.7979 8.207545 9.713175 ZT4-7 6.8581900000000005 6.8581900000000005 6.8581900000000005 ZT8-11 6.32665 6.32665 6.32665 ZT12-15 10.163145 9.834154999999999 10.492135000000001 ZT16-19 9.21487 9.21487 9.21487 ZT20-23 9.259979999999999 9.259979999999999 9.259979999999999