condition mean min max ZT0-3 1472.686883 1472.686883 1472.686883 ZT4-7 1321.9387995 1321.9387995 1321.9387995 ZT8-11 1054.3893365 1054.3893365 1054.3893365 ZT12-15 1309.9881775 1309.9881775 1309.9881775 ZT16-19 1548.2261644999999 1548.2261644999999 1548.2261644999999 ZT20-23 1653.7826655 1653.7826655 1653.7826655