condition mean min max ZT0-3 5.93586 5.93586 5.93586 ZT4-7 4.16761 4.16761 4.16761 ZT8-11 3.5617 3.5617 3.5617 ZT12-15 4.5198149999999995 4.5198149999999995 4.5198149999999995 ZT16-19 6.894410000000001 6.894410000000001 6.894410000000001 ZT20-23 6.234555 6.234555 6.234555