condition mean min max ZT0-3 17.055505 17.055505 17.055505 ZT4-7 25.4028975 25.4028975 25.4028975 ZT8-11 19.773456 19.773456 19.773456 ZT12-15 18.664581499999997 18.664581499999997 18.664581499999997 ZT16-19 20.745623000000002 20.745623000000002 20.745623000000002 ZT20-23 21.2910695 21.2910695 21.2910695