condition mean min max ZT0-3 18.170275 17.426099999999998 18.914450000000002 ZT4-7 15.133500000000002 15.133500000000002 15.133500000000002 ZT8-11 14.5598 14.5598 14.5598 ZT12-15 0 0 0 ZT16-19 18.52545 18.52545 18.52545 ZT20-23 20.1254 20.1254 20.1254