condition mean min max ZT0-3 13.767975 12.2681 15.26785 ZT4-7 17.11065 17.11065 17.11065 ZT8-11 7.359975 7.359975 7.359975 ZT12-15 0 0 0 ZT16-19 9.352915 9.352915 9.352915 ZT20-23 15.320450000000001 15.320450000000001 15.320450000000001