condition mean min max ZT0-3 8.26116 8.26116 8.26116 ZT4-7 4.862635 4.862635 4.862635 ZT8-11 7.867335 7.867335 7.867335 ZT12-15 9.33413 9.33413 9.33413 ZT16-19 13.22755 13.22755 13.22755 ZT20-23 11.22115 11.22115 11.22115