设随机变量ξ服从正态分布N(2,9),若P(ξ>c+1)=P(ξ<c-1),则c=[ ]
A.1
B.2
C.3
D.4
答案:B
---Shall we go hiking tomorrow? -----______.The radio says it will rain .
A.Sure
B.That’s a good idea
C.I’m afraid I can’t
D.All right
肾血管平滑肌脂肪瘤出现症状时以哪种表现最多见()
A.血尿
B.少尿
C.腹部疼痛
D.呕吐
E.恶心