condition mean min max ZT0-3 4.8177200000000004 4.8177200000000004 4.8177200000000004 ZT4-7 5.162375 5.162375 5.162375 ZT8-11 7.8383199999999995 7.8383199999999995 7.8383199999999995 ZT12-15 9.716940000000001 9.716940000000001 9.716940000000001 ZT16-19 11.1389 11.1389 11.1389 ZT20-23 6.234236666666667 6.234236666666667 6.234236666666667