condition mean min max ZT0-3 21.553775 20.50955 22.598 ZT4-7 12.4404 12.4404 12.4404 ZT8-11 12.23475 12.23475 12.23475 ZT12-15 0 0 0 ZT16-19 30.86685 30.86685 30.86685 ZT20-23 26.5044 26.5044 26.5044