condition mean min max ZT0-3 23.206891 23.206891 23.206891 ZT4-7 23.876058 23.876058 23.876058 ZT8-11 22.71089 22.71089 22.71089 ZT12-15 21.599848 21.599848 21.599848 ZT16-19 19.360720999999998 19.360720999999998 19.360720999999998 ZT20-23 20.2418175 20.2418175 20.2418175