condition mean min max ZT0-3 13.534054 13.534054 13.534054 ZT4-7 15.273260500000001 15.273260500000001 15.273260500000001 ZT8-11 16.312598 16.312598 16.312598 ZT12-15 20.891356000000002 20.891356000000002 20.891356000000002 ZT16-19 28.8599805 28.8599805 28.8599805 ZT20-23 29.305767 29.305767 29.305767