condition mean min max ZT0-3 7.863882 7.863882 7.863882 ZT4-7 7.629811999999999 7.629811999999999 7.629811999999999 ZT8-11 9.071340500000002 9.071340500000002 9.071340500000002 ZT12-15 9.002591500000001 9.002591500000001 9.002591500000001 ZT16-19 8.795158 8.795158 8.795158 ZT20-23 8.6182315 8.6182315 8.6182315