condition mean min max ZT0-3 8.099755 8.099755 8.099755 ZT4-7 4.5022400000000005 4.5022400000000005 4.5022400000000005 ZT8-11 7.53348 7.53348 7.53348 ZT12-15 5.838844999999999 5.838844999999999 5.838844999999999 ZT16-19 8.91765 8.91765 8.91765 ZT20-23 9.525685 9.525685 9.525685