condition mean min max ZT0-3 18.631375 17.0531 20.20965 ZT4-7 11.6486 11.6486 11.6486 ZT8-11 7.93496 7.93496 7.93496 ZT12-15 0 0 0 ZT16-19 11.6175 11.6175 11.6175 ZT20-23 15.727450000000001 15.727450000000001 15.727450000000001