condition mean min max ZT0-3 1.9890283485 1.6576525169999998 2.32040418 ZT4-7 4.9231927615 3.401883882 6.4445016410000004 ZT8-11 8.26325359 7.462299703999999 9.064207476 ZT12-15 6.28766897 4.9517636935 7.6235742465000005 ZT16-19 6.9719958315 5.966320285 7.977671378 ZT20-23 7.7997406025 7.245913271999999 8.353567933