condition mean min max ZT0-3 20.950000000000003 20.950000000000003 20.950000000000003 ZT4-7 27.5 27.5 27.5 ZT8-11 15.55 15.55 15.55 ZT12-15 13.6 13.6 13.6 ZT16-19 13.9 13.9 13.9 ZT20-23 31.049999999999997 31.049999999999997 31.049999999999997