condition mean min max ZT0-3 4.347743333333334 3.82016 5.134955 ZT4-7 4.671475 4.671475 4.671475 ZT8-11 4.78257 4.78257 4.78257 ZT12-15 8.3621875 8.307929999999999 8.416445 ZT16-19 6.611665 6.611665 6.611665 ZT20-23 5.55087 5.55087 5.55087