condition mean min max ZT0-3 1.92080839475 1.3682849190000002 2.4733318705 ZT4-7 4.795886139749999 4.062334724 5.5294375554999995 ZT8-11 5.3439158895 4.775647078 5.912184700999999 ZT12-15 12.643826625500001 9.641037561000001 15.64661569 ZT16-19 16.6221063175 15.84934308 17.394869555 ZT20-23 20.987163879999997 20.35243907 21.62188869