## Checking the Goodness of Fit of the Poisson Distribution in R for Alpha Decay by Americium-241

April 14, 2013 2 Comments

#### Introduction

Today, I will discuss the alpha decay of americium-241 and use R to model the number of emissions from a real data set with the Poisson distribution. I was especially intrigued in learning about the use of Am-241 in smoke detectors, and I will elaborate on this clever application. I will then use the Pearson chi-squared test to check the goodness of fit of my model. The R script for the full analysis is given at the end of the post; there is a particularly useful code for superscripting the mass number of a chemical isotope in the title of a plot. While there are many examples of superscripts in plot titles and axes that can be found on the web, none showed how to put the superscript before a text. I hope that this and other tricks in this script are of use to you.

Smoke Detector with Americium-241

Source: Creative Commons via Eric Mason’s Coursework for Physics 241 at Stanford University

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