condition mean min max ZT0-3 3.3225499999999997 3.3225499999999997 3.3225499999999997 ZT4-7 2.7817350000000003 2.7817350000000003 2.7817350000000003 ZT8-11 4.0007649999999995 4.0007649999999995 4.0007649999999995 ZT12-15 5.304325 5.304325 5.304325 ZT16-19 4.241325 4.241325 4.241325 ZT20-23 2.758035 2.758035 2.758035