condition mean min max ZT0-3 6.508372516666666 6.131158429333333 6.885586603999999 ZT4-7 7.9953150585 7.719039218000001 8.271590899 ZT8-11 7.5852862245 7.313134986 7.857437463 ZT12-15 8.432875955833333 7.986633578 8.879118333666666 ZT16-19 8.8621535985 8.457861045333333 9.266446151666667 ZT20-23 8.764259514333332 8.673465244666666 8.855053783999999