condition mean min max ZT0-3 6.568543333333333 3.66423 9.641735 ZT4-7 5.526815 5.526815 5.526815 ZT8-11 8.781970000000001 8.781970000000001 8.781970000000001 ZT12-15 6.7762 3.09408 10.45832 ZT16-19 8.03039 8.03039 8.03039 ZT20-23 10.229845000000001 10.229845000000001 10.229845000000001