condition mean min max ZT0-3 8.0 8.0 8.0 ZT4-7 6.7 6.7 6.7 ZT8-11 2.5999999999999996 2.5999999999999996 2.5999999999999996 ZT12-15 5.5 5.5 5.5 ZT16-19 6.25 6.25 6.25 ZT20-23 15.899999999999999 15.899999999999999 15.899999999999999