condition mean min max ZT0-3 284.623485 284.623485 284.623485 ZT4-7 293.2511765 293.2511765 293.2511765 ZT8-11 324.7088465 324.7088465 324.7088465 ZT12-15 347.52183349999996 347.52183349999996 347.52183349999996 ZT16-19 344.32852249999996 344.32852249999996 344.32852249999996 ZT20-23 371.978887 371.978887 371.978887