condition mean min max ZT0-3 63.30191666666667 44.45845 74.5052 ZT4-7 33.050399999999996 33.050399999999996 33.050399999999996 ZT8-11 21.5441 21.5441 21.5441 ZT12-15 25.625700000000002 25.33845 25.912950000000002 ZT16-19 31.262 31.262 31.262 ZT20-23 53.8198 53.8198 53.8198