condition mean min max ZT0-3 31.364387 31.364387 31.364387 ZT4-7 25.315623000000002 25.315623000000002 25.315623000000002 ZT8-11 19.318094000000002 19.318094000000002 19.318094000000002 ZT12-15 18.216855 18.216855 18.216855 ZT16-19 14.371838499999999 14.371838499999999 14.371838499999999 ZT20-23 13.742286 13.742286 13.742286