condition mean min max ZT0-3 3.721433333333333 2.470395 4.396515 ZT4-7 1.71717 1.71717 1.71717 ZT8-11 2.88518 2.88518 2.88518 ZT12-15 3.90488 3.559985 4.249775 ZT16-19 2.444265 2.444265 2.444265 ZT20-23 4.132615 4.132615 4.132615