condition mean min max ZT0-3 25.69335 24.01975 27.36695 ZT4-7 21.17905 21.17905 21.17905 ZT8-11 37.26995 37.26995 37.26995 ZT12-15 0 0 0 ZT16-19 36.122150000000005 36.122150000000005 36.122150000000005 ZT20-23 30.1552 30.1552 30.1552