condition mean min max ZT0-3 9.75 9.75 9.75 ZT4-7 6.3 6.3 6.3 ZT8-11 32.75 32.75 32.75 ZT12-15 21.049999999999997 21.049999999999997 21.049999999999997 ZT16-19 30.6 30.6 30.6 ZT20-23 13.8 13.8 13.8