condition mean min max ZT0-3 5.733665 5.733665 5.733665 ZT4-7 5.4969149999999996 5.4969149999999996 5.4969149999999996 ZT8-11 9.45891 9.45891 9.45891 ZT12-15 9.409130000000001 9.409130000000001 9.409130000000001 ZT16-19 9.901005 9.901005 9.901005 ZT20-23 6.226305 6.226305 6.226305