condition mean min max ZT0-3 19.966779 19.966779 19.966779 ZT4-7 18.9480905 18.9480905 18.9480905 ZT8-11 17.3589875 17.3589875 17.3589875 ZT12-15 18.0587715 18.0587715 18.0587715 ZT16-19 17.489063 17.489063 17.489063 ZT20-23 18.7153955 18.7153955 18.7153955