condition mean min max ZT0-3 4.699999999999999 4.699999999999999 4.699999999999999 ZT4-7 6.4 6.4 6.4 ZT8-11 30.65 30.65 30.65 ZT12-15 4.3 4.3 4.3 ZT16-19 7.75 7.75 7.75 ZT20-23 23.0 23.0 23.0