condition mean min max ZT0-3 2.1398099999999998 2.1398099999999998 2.1398099999999998 ZT4-7 2.06635 2.06635 2.06635 ZT8-11 2.4339399999999998 2.4339399999999998 2.4339399999999998 ZT12-15 2.869945 2.869945 2.869945 ZT16-19 3.246105 3.246105 3.246105 ZT20-23 2.947825 2.947825 2.947825