condition mean min max ZT0-3 31.227693 31.227693 31.227693 ZT4-7 64.08878899999999 64.08878899999999 64.08878899999999 ZT8-11 13.8605935 13.8605935 13.8605935 ZT12-15 12.986997500000001 12.986997500000001 12.986997500000001 ZT16-19 10.432388 10.432388 10.432388 ZT20-23 8.9980645 8.9980645 8.9980645