ABSTRACT
The probability distribution for the random variable Y is known as a negative binomial distribution. Its formula is given in the next box, together with the mean and variance for a negative binomial random variable. A manufacturer uses electrical fuses in an electronic system. The fuses are purchased in large lots and tested sequentially until the first defective fuse is observed. An experiment is conducted to select a suitable catalyst for the commercial production of ethylene-diamine, a product used in soaps. Suppose a chemical engineer randomly selects 3 catalysts for testing from among a group of 10 catalysts, 6 of which have low acidity and 4 of which have high acidity. The number of new jobs submitted to a computer in any one minute, the number of fatal accidents per month in a manufacturing plant, and the number of visible defects in a diamond are variables whose relative frequency distributions can be approximated well by Poisson probability distributions.
