condition mean min max ZT0-3 2.763603333333333 2.35703 3.318125 ZT4-7 3.1018299999999996 3.1018299999999996 3.1018299999999996 ZT8-11 3.35963 3.35963 3.35963 ZT12-15 3.0954125 2.710175 3.48065 ZT16-19 2.62627 2.62627 2.62627 ZT20-23 3.03925 3.03925 3.03925