condition mean min max ZT0-3 8.584 8.584 8.584 ZT4-7 7.543305 7.543305 7.543305 ZT8-11 7.02389 7.02389 7.02389 ZT12-15 7.390445 7.390445 7.390445 ZT16-19 7.740015 7.740015 7.740015 ZT20-23 8.729495 8.729495 8.729495