condition mean min max ZT0-3 12.929425 11.7817 14.07715 ZT4-7 10.8843 10.8843 10.8843 ZT8-11 17.08645 17.08645 17.08645 ZT12-15 0 0 0 ZT16-19 20.411900000000003 20.411900000000003 20.411900000000003 ZT20-23 15.524750000000001 15.524750000000001 15.524750000000001