condition mean min max ZT0-3 1.1221793333333334 0.972083 1.2266050000000002 ZT4-7 1.17563 1.17563 1.17563 ZT8-11 0.9450149999999999 0.9450149999999999 0.9450149999999999 ZT12-15 2.044095 1.91837 2.16982 ZT16-19 1.893435 1.893435 1.893435 ZT20-23 1.21299 1.21299 1.21299