condition mean min max ZT0-3 10.420526666666667 9.41449 11.47475 ZT4-7 16.89815 16.89815 16.89815 ZT8-11 15.757100000000001 15.757100000000001 15.757100000000001 ZT12-15 19.969475000000003 19.5958 20.34315 ZT16-19 14.612200000000001 14.612200000000001 14.612200000000001 ZT20-23 10.99305 10.99305 10.99305