condition mean min max ZT0-3 18.808041 18.808041 18.808041 ZT4-7 14.4775185 14.4775185 14.4775185 ZT8-11 14.825172 14.825172 14.825172 ZT12-15 15.131796000000001 15.131796000000001 15.131796000000001 ZT16-19 16.475851 16.475851 16.475851 ZT20-23 17.962145999999997 17.962145999999997 17.962145999999997