condition mean min max ZT0-3 5.579505 4.6781299999999995 6.480880000000001 ZT4-7 2.73718 2.73718 2.73718 ZT8-11 4.151285 4.151285 4.151285 ZT12-15 0 0 0 ZT16-19 7.536735 7.536735 7.536735 ZT20-23 6.8422350000000005 6.8422350000000005 6.8422350000000005