condition mean min max ZT0-3 15.782965 15.782965 15.782965 ZT4-7 23.238733 23.238733 23.238733 ZT8-11 19.522589 19.522589 19.522589 ZT12-15 16.731979000000003 16.731979000000003 16.731979000000003 ZT16-19 18.1908465 18.1908465 18.1908465 ZT20-23 17.551387 17.551387 17.551387