A.負相關 B.正相關 C.無關 D.以上說法都不對
A.50 B.25.1035 C.31.1035 D.28.35
A.2元/千克,0.011元/千克 B.2元/干克,0.09元/千克 C.1.8元/千克,0.011元/千克 D.1.8元/千克,0.09元/千克