condition mean min max ZT0-3 3.26924 2.357135 4.181345 ZT4-7 15.07859 15.07859 15.07859 ZT8-11 21.6061 21.6061 21.6061 ZT12-15 0 0 0 ZT16-19 2.35291 2.35291 2.35291 ZT20-23 3.53521 3.53521 3.53521