condition mean min max ZT0-3 8.669203 8.669203 8.669203 ZT4-7 8.30566 8.30566 8.30566 ZT8-11 9.391829 9.391829 9.391829 ZT12-15 8.0194855 8.0194855 8.0194855 ZT16-19 9.781179999999999 9.781179999999999 9.781179999999999 ZT20-23 8.89432 8.89432 8.89432