condition mean min max ZT0-3 6.800000000000001 6.800000000000001 6.800000000000001 ZT4-7 10.8 10.8 10.8 ZT8-11 14.899999999999999 14.899999999999999 14.899999999999999 ZT12-15 6.25 6.25 6.25 ZT16-19 7.449999999999999 7.449999999999999 7.449999999999999 ZT20-23 4.0 4.0 4.0