condition mean min max ZT0-3 16.369711666666667 8.493835 21.990900000000003 ZT4-7 7.348464999999999 7.348464999999999 7.348464999999999 ZT8-11 10.15086 10.15086 10.15086 ZT12-15 14.868725000000001 13.72395 16.0135 ZT16-19 16.6899 16.6899 16.6899 ZT20-23 23.01815 23.01815 23.01815