condition mean min max ZT0-3 11.2704725 9.317195 13.223749999999999 ZT4-7 6.39802 6.39802 6.39802 ZT8-11 8.26682 8.26682 8.26682 ZT12-15 0 0 0 ZT16-19 9.033045000000001 9.033045000000001 9.033045000000001 ZT20-23 8.4415 8.4415 8.4415