condition mean min max ZT0-3 2.147711666666667 1.177205 3.69911 ZT4-7 4.649655 4.649655 4.649655 ZT8-11 2.8240149999999997 2.8240149999999997 2.8240149999999997 ZT12-15 8.0224075 6.277165 9.76765 ZT16-19 4.240955 4.240955 4.240955 ZT20-23 3.477515 3.477515 3.477515