condition mean min max ZT0-3 11.928175 10.9818 12.87455 ZT4-7 7.04766 7.04766 7.04766 ZT8-11 9.795095 9.795095 9.795095 ZT12-15 0 0 0 ZT16-19 10.126384999999999 10.126384999999999 10.126384999999999 ZT20-23 9.51922 9.51922 9.51922