condition mean min max ZT0-3 18.25 18.25 18.25 ZT4-7 19.9 19.9 19.9 ZT8-11 11.100000000000001 11.100000000000001 11.100000000000001 ZT12-15 22.75 22.75 22.75 ZT16-19 22.8 22.8 22.8 ZT20-23 2.25 2.25 2.25