condition mean min max ZT0-3 2.798425 0.65543 4.484445 ZT4-7 3.090485 3.090485 3.090485 ZT8-11 3.817295 3.817295 3.817295 ZT12-15 1.34953425 0.9805625 1.718506 ZT16-19 6.305445000000001 6.305445000000001 6.305445000000001 ZT20-23 5.775415000000001 5.775415000000001 5.775415000000001