# Question on stat theory

1. Jan 27, 2014

### joshmccraney

hey pf!

can someone help me understand why a pdf is defined in the following manner: $$\lim_{\substack{N\to \infty\\ \Delta c \to 0}}\frac{H(c,\Delta c,N)}{\Delta c}$$ where $\Delta c$ is the width, $N$ is the observation number? Specifically, why the divisor? why is this necessary? $H$ is a histogram.

any insight is greatly appreciated!

thanks!

Last edited: Jan 27, 2014
2. Jan 27, 2014

### mathman

I'm not familiar with your notation. However, in general, the integral of a pdf must be 1, so I presume the division is to insure that this holds.

3. Jan 27, 2014

### joshmccraney

sorry, i was worried about being too vague, but i think youre right.