condition mean min max ZT0-3 7.283861666666667 4.4687149999999995 9.06442 ZT4-7 3.90069 3.90069 3.90069 ZT8-11 3.6872 3.6872 3.6872 ZT12-15 5.54471 4.809255 6.280165 ZT16-19 6.22079 6.22079 6.22079 ZT20-23 10.561425 10.561425 10.561425