0- Variable : A variable is represented by a symbol (X, Y, A, B...) and it can take on any of a specified set of values.
- Random Variable: When the value of a variable is the outcome of an experiment, the variable is called a random variable.
- A continuous random variable is one where the outcomes can be any value on a continuous scale.
- p.d.f : probability density function f(x) is a smooth version of a histogram.
- If X is a random variable with p.d.f f(x) then
- f(x)≥ 0 since we cannot have negative probabilities.
- P(a<X<b) =a∫b f(x) dx
- -∞∫∞ f(x)dx = 1 since the area under the curve = 1
