condition mean min max ZT0-3 20.285575 19.73885 20.8323 ZT4-7 33.87895 33.87895 33.87895 ZT8-11 25.538600000000002 25.538600000000002 25.538600000000002 ZT12-15 0 0 0 ZT16-19 17.8985 17.8985 17.8985 ZT20-23 26.2118 26.2118 26.2118