condition mean min max ZT0-3 5.050466666666667 4.50531 5.431635 ZT4-7 8.37276 8.37276 8.37276 ZT8-11 14.25715 14.25715 14.25715 ZT12-15 6.445465 5.26107 7.62986 ZT16-19 7.1163799999999995 7.1163799999999995 7.1163799999999995 ZT20-23 4.809945 4.809945 4.809945