condition mean min max ZT0-3 36.204616666666666 32.8625 41.45325 ZT4-7 37.75185 37.75185 37.75185 ZT8-11 21.6421 21.6421 21.6421 ZT12-15 22.500500000000002 17.33885 27.66215 ZT16-19 18.668950000000002 18.668950000000002 18.668950000000002 ZT20-23 23.4664 23.4664 23.4664