condition mean min max ZT0-3 30.789898 30.789898 30.789898 ZT4-7 36.2943085 36.2943085 36.2943085 ZT8-11 29.288666999999997 29.288666999999997 29.288666999999997 ZT12-15 23.804507 23.804507 23.804507 ZT16-19 17.233749500000002 17.233749500000002 17.233749500000002 ZT20-23 16.861534 16.861534 16.861534