condition mean min max ZT0-3 4.3545653605000005 3.5466287029999997 5.1625020180000005 ZT4-7 3.0677470335 2.888404522 3.2470895449999997 ZT8-11 2.50382786025 2.303310048 2.7043456724999997 ZT12-15 1.5749401855 1.2429868544999998 1.9068935165000003 ZT16-19 1.470647705 1.2025716995 1.7387237105 ZT20-23 2.7275123590000003 2.6214598860000002 2.8335648320000004