The combination of probability curves in engineering

ENGINEERS are quite familiar with simple probability distributions showing the relative likelihoods of occurrence of the different values which a varying physical or electrical quantity may assume. As the complexities of machines and circuits in modern design increase, it becomes highly desirable to be able to estimate the probability distribution resulting from the joint presence of two or more sources of variation. This paper will undertake to present something of the theory of making such combinations, and its application to a number of practical examples.