condition mean min max ZT0-3 11.6 11.6 11.6 ZT4-7 17.4 17.4 17.4 ZT8-11 37.6 37.6 37.6 ZT12-15 2.8499999999999996 2.8499999999999996 2.8499999999999996 ZT16-19 3.45 3.45 3.45 ZT20-23 3.75 3.75 3.75