condition mean min max ZT0-3 2.9289300000000003 2.9289300000000003 2.9289300000000003 ZT4-7 3.01498 3.01498 3.01498 ZT8-11 2.2992999999999997 2.2992999999999997 2.2992999999999997 ZT12-15 2.00333 2.00333 2.00333 ZT16-19 2.8507949999999997 2.8507949999999997 2.8507949999999997 ZT20-23 2.21441 2.21441 2.21441