condition mean min max ZT0-3 21.568915 9.655795 32.6602 ZT4-7 15.2555 15.2555 15.2555 ZT8-11 15.5276 15.5276 15.5276 ZT12-15 14.83645 13.3441 16.3288 ZT16-19 25.275199999999998 25.275199999999998 25.275199999999998 ZT20-23 31.902549999999998 31.902549999999998 31.902549999999998