condition mean min max ZT0-3 22.933648 22.933648 22.933648 ZT4-7 19.3258665 19.3258665 19.3258665 ZT8-11 19.203415 19.203415 19.203415 ZT12-15 20.0927175 20.0927175 20.0927175 ZT16-19 17.548519 17.548519 17.548519 ZT20-23 17.0251565 17.0251565 17.0251565