condition mean min max ZT0-3 12.7 12.7 12.7 ZT4-7 2.9 2.9 2.9 ZT8-11 39.449999999999996 39.449999999999996 39.449999999999996 ZT12-15 21.9 21.9 21.9 ZT16-19 20.45 20.45 20.45 ZT20-23 9.6 9.6 9.6