condition mean min max ZT0-3 9.829637 9.829637 9.829637 ZT4-7 9.783111 9.783111 9.783111 ZT8-11 8.8000975 8.8000975 8.8000975 ZT12-15 9.656115499999999 9.656115499999999 9.656115499999999 ZT16-19 10.731067 10.731067 10.731067 ZT20-23 10.324121 10.324121 10.324121