condition mean min max ZT0-3 9.196615 8.7326 9.66063 ZT4-7 9.383605 9.383605 9.383605 ZT8-11 7.509105 7.509105 7.509105 ZT12-15 0 0 0 ZT16-19 9.187775 9.187775 9.187775 ZT20-23 8.2257 8.2257 8.2257