condition mean min max ZT0-3 2.101845 2.101845 2.101845 ZT4-7 1.6885599999999998 1.6885599999999998 1.6885599999999998 ZT8-11 1.56312 1.56312 1.56312 ZT12-15 2.619045 2.619045 2.619045 ZT16-19 3.0372950000000003 3.0372950000000003 3.0372950000000003 ZT20-23 1.829275 1.829275 1.829275