condition mean min max ZT0-3 4.969993333333333 3.230105 7.307735 ZT4-7 1.52692 1.52692 1.52692 ZT8-11 1.6026 1.6026 1.6026 ZT12-15 5.1254 3.55622 6.69458 ZT16-19 3.8278550000000005 3.8278550000000005 3.8278550000000005 ZT20-23 6.038575 6.038575 6.038575