condition mean min max ZT0-3 6.620603333333333 4.285825 8.53909 ZT4-7 6.422655000000001 6.422655000000001 6.422655000000001 ZT8-11 4.83157 4.83157 4.83157 ZT12-15 11.95944 11.278749999999999 12.640130000000001 ZT16-19 14.613600000000002 14.613600000000002 14.613600000000002 ZT20-23 10.42685 10.42685 10.42685