condition mean min max ZT0-3 10.4 10.4 10.4 ZT4-7 11.5 11.5 11.5 ZT8-11 28.549999999999997 28.549999999999997 28.549999999999997 ZT12-15 22.700000000000003 22.700000000000003 22.700000000000003 ZT16-19 11.55 11.55 11.55 ZT20-23 9.4 9.4 9.4