condition mean min max ZT0-3 16.983432 16.983432 16.983432 ZT4-7 17.674563 17.674563 17.674563 ZT8-11 17.449285 17.449285 17.449285 ZT12-15 18.6227935 18.6227935 18.6227935 ZT16-19 15.167039500000001 15.167039500000001 15.167039500000001 ZT20-23 15.216666 15.216666 15.216666