condition mean min max ZT0-3 20.65 20.65 20.65 ZT4-7 12.0 12.0 12.0 ZT8-11 6.5 6.5 6.5 ZT12-15 2.8499999999999996 2.8499999999999996 2.8499999999999996 ZT16-19 8.45 8.45 8.45 ZT20-23 6.0 6.0 6.0