统计概念问题 ,If X follows a normal distribution with μ=30 ,σ=5 ,t

统计概念问题 ,
If X follows a normal distribution with μ=30 ,σ=5 ,then P(X=40)?
a.  0.0108                    b.0           c.  0.4772              d.  0.5    e.none of the above
the location of a nomal curve is determined by
a.mean       b.range          c.standard deviation      d.variance       e.none of a above
the shape of a nomal curve is determined by
   a.mean         b.range          c.standard deviation         d.mode         e.none of a above
4.which one of the following distributions is a special case of Gamma distribution
 a.exponential         b.uniform             c.chi-square          d.both(A)and (B)         e.both (A)and (C)
5.the number of collisions at sea in year is Possion distributed.THus,the length of time between collisions follow:
a.  a Poisson distribution       b.a nomal distribution         c.an exponential distribution      d.a Bernoulli distribution         e.none of the above