condition mean min max ZT0-3 9.971779 9.971779 9.971779 ZT4-7 9.091123499999998 9.091123499999998 9.091123499999998 ZT8-11 9.2943705 9.2943705 9.2943705 ZT12-15 9.066801 9.066801 9.066801 ZT16-19 8.822891 8.822891 8.822891 ZT20-23 9.376018 9.376018 9.376018