condition mean min max ZT0-3 1.7364600000000001 1.7364600000000001 1.7364600000000001 ZT4-7 1.742873 1.742873 1.742873 ZT8-11 2.90734 2.90734 2.90734 ZT12-15 3.323475 3.323475 3.323475 ZT16-19 3.0322199999999997 3.0322199999999997 3.0322199999999997 ZT20-23 1.6648399999999999 1.6648399999999999 1.6648399999999999