condition mean min max ZT0-3 21.180625 20.05385 22.3074 ZT4-7 20.95635 20.95635 20.95635 ZT8-11 18.8646 18.8646 18.8646 ZT12-15 0 0 0 ZT16-19 41.73495 41.73495 41.73495 ZT20-23 25.21435 25.21435 25.21435