condition mean min max ZT0-3 3.345395 3.345395 3.345395 ZT4-7 2.22365 2.22365 2.22365 ZT8-11 5.1152750000000005 5.1152750000000005 5.1152750000000005 ZT12-15 12.079085 12.079085 12.079085 ZT16-19 11.608630000000002 11.608630000000002 11.608630000000002 ZT20-23 5.7571200000000005 5.7571200000000005 5.7571200000000005