# Probability density function

1. Dec 31, 2012

### reddvoid

If probability distribution function is flat like a rectangular signal then probability density function which is differentiation of probability distribution function will have positive and negative impulses, but probability density function cannot be negative. . whats wrong in this . . . Can't probability distribution functio be flat ?

2. Jan 1, 2013

### Staff: Mentor

Sometimes, "probability distribution function" is used as "probability density function".

3. Jan 3, 2013

### Enthalpy

The differentiated function is not a probability.

4. Jan 3, 2013

### rbj

neither is the rectangular function a distribution function. a distribution function must be an increasing function (so that the derivative, which is the p.d.f., is always non-negative).