condition mean min max ZT0-3 18.556413 18.556413 18.556413 ZT4-7 14.6854515 14.6854515 14.6854515 ZT8-11 16.1479155 16.1479155 16.1479155 ZT12-15 18.4444865 18.4444865 18.4444865 ZT16-19 20.2985575 20.2985575 20.2985575 ZT20-23 18.3563405 18.3563405 18.3563405