condition mean min max ZT0-3 0.396381938 0.321209487 0.471554389 ZT4-7 1.50419866475 1.214161858 1.7942354715 ZT8-11 3.57810868375 2.4105297905 4.745687577 ZT12-15 8.7492768545 7.717191269000001 9.781362439999999 ZT16-19 8.503198908249999 8.241499292499999 8.764898524 ZT20-23 9.186845964749999 8.8607536515 9.512938278