condition mean min max ZT0-3 9.438498333333333 6.233645 11.2196 ZT4-7 7.045249999999999 7.045249999999999 7.045249999999999 ZT8-11 9.64491 9.64491 9.64491 ZT12-15 18.002724999999998 16.50375 19.5017 ZT16-19 15.628350000000001 15.628350000000001 15.628350000000001 ZT20-23 17.589100000000002 17.589100000000002 17.589100000000002