condition mean min max ZT0-3 4.091195000000001 4.053785 4.128605 ZT4-7 5.4213249999999995 5.4213249999999995 5.4213249999999995 ZT8-11 5.160629999999999 5.160629999999999 5.160629999999999 ZT12-15 0 0 0 ZT16-19 5.686685000000001 5.686685000000001 5.686685000000001 ZT20-23 5.50921 5.50921 5.50921