condition mean min max ZT0-3 8.948263 8.948263 8.948263 ZT4-7 8.442133 8.442133 8.442133 ZT8-11 9.501823000000002 9.501823000000002 9.501823000000002 ZT12-15 8.862276000000001 8.862276000000001 8.862276000000001 ZT16-19 9.745749 9.745749 9.745749 ZT20-23 8.2447975 8.2447975 8.2447975