condition mean min max ZT0-3 8.616885 8.4894 8.74437 ZT4-7 8.884955 8.884955 8.884955 ZT8-11 4.57045 4.57045 4.57045 ZT12-15 0 0 0 ZT16-19 6.6142900000000004 6.6142900000000004 6.6142900000000004 ZT20-23 8.27976 8.27976 8.27976