condition mean min max ZT0-3 16.587421 16.587421 16.587421 ZT4-7 14.3281705 14.3281705 14.3281705 ZT8-11 18.800359 18.800359 18.800359 ZT12-15 21.713995500000003 21.713995500000003 21.713995500000003 ZT16-19 22.650434500000003 22.650434500000003 22.650434500000003 ZT20-23 15.528478 15.528478 15.528478