condition mean min max ZT0-3 1.5102883333333332 1.22016 1.8773650000000002 ZT4-7 1.253615 1.253615 1.253615 ZT8-11 1.341155 1.341155 1.341155 ZT12-15 2.0061074999999997 1.890695 2.12152 ZT16-19 2.291335 2.291335 2.291335 ZT20-23 2.7943800000000003 2.7943800000000003 2.7943800000000003