condition mean min max ZT0-3 26.012479 26.012479 26.012479 ZT4-7 29.1181195 29.1181195 29.1181195 ZT8-11 26.966368000000003 26.966368000000003 26.966368000000003 ZT12-15 27.273438499999997 27.273438499999997 27.273438499999997 ZT16-19 27.5852925 27.5852925 27.5852925 ZT20-23 27.826230000000002 27.826230000000002 27.826230000000002