condition mean min max ZT0-3 4.616098333333333 1.8664200000000002 6.45079 ZT4-7 2.621055 2.621055 2.621055 ZT8-11 4.457305 4.457305 4.457305 ZT12-15 6.90936 5.881985 7.9367350000000005 ZT16-19 9.2019 9.2019 9.2019 ZT20-23 8.7911 8.7911 8.7911