condition mean min max ZT0-3 5.413426666666666 4.464535 5.952584999999999 ZT4-7 4.659655 4.659655 4.659655 ZT8-11 6.140965 6.140965 6.140965 ZT12-15 7.749675 7.6808250000000005 7.818525 ZT16-19 7.35092 7.35092 7.35092 ZT20-23 5.77008 5.77008 5.77008