condition mean min max ZT0-3 17.5051 17.5051 17.5051 ZT4-7 18.0034 18.0034 18.0034 ZT8-11 7.883330000000001 7.883330000000001 7.883330000000001 ZT12-15 7.575239999999999 7.575239999999999 7.575239999999999 ZT16-19 11.8014 11.8014 11.8014 ZT20-23 16.2148 16.2148 16.2148