condition mean min max ZT0-3 7.242928333333334 4.37762 9.455525000000002 ZT4-7 4.59777 4.59777 4.59777 ZT8-11 7.143834999999999 7.143834999999999 7.143834999999999 ZT12-15 14.850625 14.456050000000001 15.2452 ZT16-19 13.32455 13.32455 13.32455 ZT20-23 15.25665 15.25665 15.25665