What is the difference between exponential and geometric distribution? I don't really understand the difference between exponential and geometric distribution.
 A: Did you try looking at Wikipedia?

The exponential distribution may be viewed as a continuous counterpart of the geometric distribution, which describes the number of Bernoulli trials necessary for a discrete process to change state. In contrast, the exponential distribution describes the time for a continuous process to change state.

A: Exponential distributions involve raising numbers to a certain power whereas geometric distributions are more general in nature and involve performing various operations on numbers such as multiplying a certain number by two continuously. Exponential distributions are more specific types of geometric distributions. 
Exponential distributions: 2, 4, 16, 256 or 3, 9, 81, 6561.
Geometric distribution: 2, 4, 8, 16, 32, 64.
Just my two cents anyway.
A: The geometric distribution belongs to the exponential family and so does "the exponential distribution". They only differ in the parameters and sufficient statistics used in factored expression for conditional distributions from the exponential family. 
