condition mean min max ZT0-3 3.5033666666666665 2.612755 4.14112 ZT4-7 3.316595 3.316595 3.316595 ZT8-11 3.616445 3.616445 3.616445 ZT12-15 4.7386125 4.523665 4.9535599999999995 ZT16-19 3.4469650000000005 3.4469650000000005 3.4469650000000005 ZT20-23 4.1300349999999995 4.1300349999999995 4.1300349999999995