condition mean min max ZT0-3 8.128125 8.128125 8.128125 ZT4-7 7.0782050000000005 7.0782050000000005 7.0782050000000005 ZT8-11 7.810644999999999 7.810644999999999 7.810644999999999 ZT12-15 7.064355 7.064355 7.064355 ZT16-19 9.997205000000001 9.997205000000001 9.997205000000001 ZT20-23 7.974755 7.974755 7.974755