condition mean min max ZT0-3 6.7449575 6.235885 7.25403 ZT4-7 6.088905 6.088905 6.088905 ZT8-11 18.61425 18.61425 18.61425 ZT12-15 0 0 0 ZT16-19 16.468600000000002 16.468600000000002 16.468600000000002 ZT20-23 13.163699999999999 13.163699999999999 13.163699999999999