condition mean min max ZT0-3 9.42365 9.42365 9.42365 ZT4-7 8.04947 8.04947 8.04947 ZT8-11 7.899800000000001 7.899800000000001 7.899800000000001 ZT12-15 7.818155000000001 7.818155000000001 7.818155000000001 ZT16-19 6.37181 6.37181 6.37181 ZT20-23 8.573115 8.573115 8.573115