condition mean min max ZT0-3 9.632439999999999 9.632439999999999 9.632439999999999 ZT4-7 7.5216449999999995 7.5216449999999995 7.5216449999999995 ZT8-11 7.325725 7.325725 7.325725 ZT12-15 7.98689 7.98689 7.98689 ZT16-19 8.2996 8.2996 8.2996 ZT20-23 9.98412 9.98412 9.98412