condition mean min max ZT0-3 21.649607 21.649607 21.649607 ZT4-7 21.32131 21.32131 21.32131 ZT8-11 21.930798 21.930798 21.930798 ZT12-15 22.268178499999998 22.268178499999998 22.268178499999998 ZT16-19 20.216732 20.216732 20.216732 ZT20-23 20.6343295 20.6343295 20.6343295