condition mean min max ZT0-3 15.239773 15.239773 15.239773 ZT4-7 17.128948 17.128948 17.128948 ZT8-11 18.4966245 18.4966245 18.4966245 ZT12-15 24.592660000000002 24.592660000000002 24.592660000000002 ZT16-19 14.085981 14.085981 14.085981 ZT20-23 17.954252 17.954252 17.954252