condition mean min max ZT0-3 4.071015602499999 3.7260559969999996 4.415975208 ZT4-7 2.7101273115 2.3142327475 3.1060218755 ZT8-11 4.7077277325 3.9205033085 5.4949521565 ZT12-15 6.254334447 5.441702072 7.0669668219999995 ZT16-19 4.61584677 4.2552581165 4.9764354235 ZT20-23 8.2336670065 6.914708705 9.552625308