condition mean min max ZT0-3 12.799999999999999 12.799999999999999 12.799999999999999 ZT4-7 5.1 5.1 5.1 ZT8-11 11.899999999999999 11.899999999999999 11.899999999999999 ZT12-15 9.1 9.1 9.1 ZT16-19 18.0 18.0 18.0 ZT20-23 7.85 7.85 7.85