condition mean min max ZT0-3 1.0011621939166666 0.9345093755 1.0678150123333334 ZT4-7 0.8813194409999999 0.872573403 0.8900654789999999 ZT8-11 0.5473843 0.5286061440000001 0.566162456 ZT12-15 0.721018503 0.6099841903333333 0.8320528156666667 ZT16-19 1.2849950375 1.192885074 1.377105001 ZT20-23 1.102431352 0.91782518 1.287037524