condition mean min max ZT0-3 227.798486 227.798486 227.798486 ZT4-7 171.2200445 171.2200445 171.2200445 ZT8-11 236.01022949999998 236.01022949999998 236.01022949999998 ZT12-15 284.7909525 284.7909525 284.7909525 ZT16-19 342.078211 342.078211 342.078211 ZT20-23 341.0857035 341.0857035 341.0857035