condition mean min max ZT0-3 30.471575 27.649 33.29415 ZT4-7 24.3461 24.3461 24.3461 ZT8-11 12.57245 12.57245 12.57245 ZT12-15 0 0 0 ZT16-19 17.381349999999998 17.381349999999998 17.381349999999998 ZT20-23 25.098550000000003 25.098550000000003 25.098550000000003