condition mean min max ZT0-3 3.2543459724999995 2.288489313 4.2202026319999995 ZT4-7 6.822246917999999 4.773471159 8.871022677 ZT8-11 6.7442343762500006 5.412114796 8.0763539565 ZT12-15 2.7000491350000004 2.6414570995 2.7586411705000002 ZT16-19 4.1302318125 3.3605842619999997 4.899879363 ZT20-23 4.56473055025 4.0739096635 5.055551437