condition mean min max ZT0-3 523.707652 523.707652 523.707652 ZT4-7 367.85269800000003 367.85269800000003 367.85269800000003 ZT8-11 383.270175 383.270175 383.270175 ZT12-15 446.7937375 446.7937375 446.7937375 ZT16-19 481.29739099999995 481.29739099999995 481.29739099999995 ZT20-23 526.934374 526.934374 526.934374