condition mean min max ZT0-3 1.6999852055 1.028793041 2.3711773700000003 ZT4-7 5.625595339 4.743284958 6.50790572 ZT8-11 7.1375570715 6.6531890055 7.6219251375 ZT12-15 10.604395372750002 9.820559287 11.388231458500002 ZT16-19 14.429521775000001 13.13864755 15.720396000000001 ZT20-23 21.388637680000002 19.844265565 22.933009795000004