## A.1 Introduction

Reliability statistical analysis can be complex. However, the basic statistics needed for industry are not too difficult and we will provide an overview of the key statistics needed for the reader. This will help in understanding the full scope of the science of degradation and its analysis. We will overview a number of methods that are common throughout the industry.

It can be somewhat incomplete to understand the physics of degradation and not understand reliability. This is because understanding and preventing failures from occurring is an inexact science. This means we have to deal with distributions and probability of failure occurring. It is not enough to understand the failure mechanism. We need to ask the following questions.

- What is the failure mechanism?
- What is the probability of it occurring?
- Can we demonstrate with a certain probability that a high failure rate will not occur on a product?
- How can we verify that failure will not occur if the product is to be in the field for 10 years?
- What types of accelerated test do we do?
- What is the sample size that is required?
- What is the confidence in our estimates?

*A.1.1 Reliability and Accelerated Testing Software to Aid the Reader*

It is helpful to use software in understanding reliability and accelerated testing analysis in Special Topics A and B. Free reliability statistics and accelerated testing software is available to aid the reader at the author’s ...