condition mean min max ZT0-3 3.7396374999999997 3.30693 4.172345 ZT4-7 5.30339 5.30339 5.30339 ZT8-11 2.646325 2.646325 2.646325 ZT12-15 0 0 0 ZT16-19 4.64825 4.64825 4.64825 ZT20-23 4.19275 4.19275 4.19275