6. Electronic, mechanical, software and human reliability...

The different sciences called upon by the SoF provide very different models.

• The very large number of "identical" electronic components on the market (and the high number of failures) has made it possible to represent their reliability using an excellent probabilistic approximation based on the "law of large numbers". It's important to realize that this probabilistic approach is relevant because of the "law of large numbers", not because it translates the laws of physics. It is for the same reason that it is used for other types of components, and the relevance of the law of large numbers needs to be re-examined. It is all too common to ignore this basis, and therefore to rely more or less unconsciously on the law of large numbers.

  Similarly, the convenient constant failure rate approximation is fair enough for many...