condition mean min max ZT0-3 16.506968 16.506968 16.506968 ZT4-7 18.0687585 18.0687585 18.0687585 ZT8-11 17.0078945 17.0078945 17.0078945 ZT12-15 16.3086325 16.3086325 16.3086325 ZT16-19 20.008826 20.008826 20.008826 ZT20-23 21.2575175 21.2575175 21.2575175