condition mean min max ZT0-3 20.599999999999998 20.599999999999998 20.599999999999998 ZT4-7 28.0 28.0 28.0 ZT8-11 6.15 6.15 6.15 ZT12-15 34.6 34.6 34.6 ZT16-19 25.85 25.85 25.85 ZT20-23 18.45 18.45 18.45