condition mean min max ZT0-3 20.43156666666667 14.95795 24.43855 ZT4-7 14.803999999999998 14.803999999999998 14.803999999999998 ZT8-11 17.728749999999998 17.728749999999998 17.728749999999998 ZT12-15 22.45115 18.478099999999998 26.4242 ZT16-19 25.612099999999998 25.612099999999998 25.612099999999998 ZT20-23 32.0185 32.0185 32.0185