condition mean min max ZT0-3 4.476575 4.476575 4.476575 ZT4-7 3.876325 3.876325 3.876325 ZT8-11 2.8387000000000002 2.8387000000000002 2.8387000000000002 ZT12-15 3.849395 3.849395 3.849395 ZT16-19 4.05967 4.05967 4.05967 ZT20-23 4.9197299999999995 4.9197299999999995 4.9197299999999995