直线回归分析中，对回归系数作假设检验，HO是（）
A.β＝0
B.ρ＝0
C.μ＝0
D.τ＝0
E.M＝0
参考答案：A
Why is Las Vegas so successful in attracting tourists
A．Because of gambling.
B．Because it is an alternative family destination.
C．Because the hotels are quite cheap.
D．Because people like the desert.
市政消火栓设置的主要技术要求？
