condition mean min max ZT0-3 13.751225 12.942 14.56045 ZT4-7 20.386 20.386 20.386 ZT8-11 25.534950000000002 25.534950000000002 25.534950000000002 ZT12-15 0 0 0 ZT16-19 28.9467 28.9467 28.9467 ZT20-23 22.198 22.198 22.198