condition mean min max ZT0-3 9.0 9.0 9.0 ZT4-7 9.0 9.0 9.0 ZT8-11 8.4 8.4 8.4 ZT12-15 7.5 7.5 7.5 ZT16-19 2.4499999999999997 2.4499999999999997 2.4499999999999997 ZT20-23 8.95 8.95 8.95