condition mean min max ZT0-3 18.263575 17.461199999999998 19.06595 ZT4-7 11.26375 11.26375 11.26375 ZT8-11 8.52327 8.52327 8.52327 ZT12-15 0 0 0 ZT16-19 14.610299999999999 14.610299999999999 14.610299999999999 ZT20-23 13.6759 13.6759 13.6759