condition mean min max ZT0-3 3.111695 3.111695 3.111695 ZT4-7 1.7949300000000001 1.7949300000000001 1.7949300000000001 ZT8-11 2.43748 2.43748 2.43748 ZT12-15 3.4060300000000003 3.4060300000000003 3.4060300000000003 ZT16-19 4.424965 4.424965 4.424965 ZT20-23 3.7727399999999998 3.7727399999999998 3.7727399999999998