condition mean min max ZT0-3 13.615643 13.615643 13.615643 ZT4-7 9.434469 9.434469 9.434469 ZT8-11 9.583251 9.583251 9.583251 ZT12-15 11.362073 11.362073 11.362073 ZT16-19 13.388129 13.388129 13.388129 ZT20-23 11.669494 11.669494 11.669494