condition mean min max ZT0-3 6.9536525000000005 6.120415 7.78689 ZT4-7 7.473135 7.473135 7.473135 ZT8-11 7.81141 7.81141 7.81141 ZT12-15 0 0 0 ZT16-19 10.7235 10.7235 10.7235 ZT20-23 8.356515 8.356515 8.356515