解：∵x-B（n,p)且Ex=3,Dx=1.5∴np=3，np(1-p)=1.5∴n=6，p=0.5∴x-B（6,0.5)∴P(x=0)=C(6,0)(0.5)^6=0.015625 P(X=6)=C(6,6)(0.5)^6=0.015625∴p(1<=x<=5)=1-P(x=0)-P(X=6)=0.96875
