condition mean min max ZT0-3 3.4404173229999997 2.4178806919999998 4.462953954 ZT4-7 7.7815969772499995 6.5126734095 9.050520545 ZT8-11 7.825754014 7.4611637355 8.1903442925 ZT12-15 5.017556625 4.2838517905 5.7512614595 ZT16-19 7.2840734627499995 5.02933836 9.5388085655 ZT20-23 16.9306760575 13.724988925000002 20.136363189999997