condition mean min max ZT0-3 2.154845 2.0111499999999998 2.29854 ZT4-7 1.882665 1.882665 1.882665 ZT8-11 1.637165 1.637165 1.637165 ZT12-15 0 0 0 ZT16-19 2.000865 2.000865 2.000865 ZT20-23 2.36045 2.36045 2.36045