condition mean min max ZT0-3 8.7 8.7 8.7 ZT4-7 6.3 6.3 6.3 ZT8-11 22.65 22.65 22.65 ZT12-15 33.699999999999996 33.699999999999996 33.699999999999996 ZT16-19 23.75 23.75 23.75 ZT20-23 11.45 11.45 11.45