condition mean min max ZT0-3 539.690979 539.690979 539.690979 ZT4-7 311.5874465 311.5874465 311.5874465 ZT8-11 72.653594 72.653594 72.653594 ZT12-15 28.7001125 28.7001125 28.7001125 ZT16-19 23.5418765 23.5418765 23.5418765 ZT20-23 34.3096515 34.3096515 34.3096515