Discrete(binomial) Distribution computations

[smgardy]

For Binomial Computations
(1)P(a<=x<=b)=F(b)-F(a-1)
(2)P(a<x<=b)=F(b)-F(a)
Then what is
(3) P(a<=x<b)=
(4) P(a<x<b)=
For continious distributions all four statements are equal, but if that was on the exam i would get burned on that question if an equality of 3 or 4 came up. Thanks.

 

[JoeyDVivre]

So everyone says that too much memorization is required on this exam and they point to things like this. If you are going to try to memorize 4 separate formulae for this and then use them on the exam, you don't have the structure down and you will just blow up.

(1) - (4) all follow from the definition of the cdf F(c) = P(X <= c) as does the statement about continuous distributions. You should work hard at understanding why and then you won't get burned on the exam.

Here are some questions you should think about:
X is continuous, what is P(X= 17)
X is binomial with n = 22 what is P(X=17)
X is binomial with n = 22 what is P(X =17.3)
X is binomial with n = 22 what is P(15 < X < 17)