![Creating a cumulative distribution [new]](https://imgdetail.ebookreading.net/cover/cover/data/EB9781849517249.jpg)
In this recipe, we show how to use another useful statistical plot hiding away in the smoothing options, and also new to gnuplot in version 4.4. The curve plotted in the next figure is closely related to the one plotted in the previous recipe. To get the following figure, just integrate the frequency distribution curve:
![Creating a cumulative distribution [new]](http://imgdetail.ebookreading.net/other/4/9781849517249/9781849517249__gnuplot-cookbook__9781849517249__graphics__7249_07_06.jpg)
The following script will get you the previous figure:
set key top left
plot 'randomnormal.text' using 1:(.001) smooth cumul
title "Cumulative distribution"
The normalization issues are the same as the kdensity discussion in the previous recipe. The only difference here is the choice of smooth cumul—an abbreviation for cumulative. We can verify that we have a properly normalized curve because it approaches 1 as we approach the endpoint on the right. This is what we should expect, because this curve gives the integral, or area, under the normalized distribution curve plotted in the previous recipe. This cumulative distribution curve tells us the probability of choosing, for any x value, a random number equal to or less than x.