condition mean min max ZT0-3 13.3853525 11.467555 15.303149999999999 ZT4-7 7.79226 7.79226 7.79226 ZT8-11 7.764635 7.764635 7.764635 ZT12-15 0 0 0 ZT16-19 9.949195 9.949195 9.949195 ZT20-23 9.48313 9.48313 9.48313