condition mean min max ZT0-3 7.204353333333334 2.30517 15.917100000000001 ZT4-7 10.08182 10.08182 10.08182 ZT8-11 4.21608 4.21608 4.21608 ZT12-15 3.563805 2.6741200000000003 4.4534899999999995 ZT16-19 3.752865 3.752865 3.752865 ZT20-23 2.0084 2.0084 2.0084