condition mean min max ZT0-3 7.699999999999999 7.699999999999999 7.699999999999999 ZT4-7 3.5 3.5 3.5 ZT8-11 2.9499999999999997 2.9499999999999997 2.9499999999999997 ZT12-15 21.25 21.25 21.25 ZT16-19 15.049999999999999 15.049999999999999 15.049999999999999 ZT20-23 18.95 18.95 18.95