Every time you make popcorn, you are listening to the normal distribution

If you are using Excel, you should use Average and Stdev to get the parameters and Normdist to draw it. For example, you can read http://excelgraphs.blogspot.com/2013/03/historgrams-and-over... (I don't like how they make the final graphs, but the article explain how to use the functions.) (Be careful, because it's easy to use the wrong x axis, and draw the Gaussian curve shifted 1/2 histogram bar.)

If you like to understand the calculations and use less magical function, you can read http://www.phys.utk.edu/labs/plstatan.pdf . (If you want to read directly the code, go to page 5 to skip the theoretical background.)