ABSTRACT
An example of a contingency table, based on the two factors in Colombo and Ihm (Colombo & Ihm 1988), is given in Table 1.
In such a contingency table we would typically be interested in whether there were differences in the probabilities or rates of failures which result in the observed numbers of failures n i ji j , , = , ,1 2 3 between the different locations or systems. Thereare two main statistical tests which could be used to do this; the Chi-Squared Test and Fisher’s Exact Test (Pearson 1900, Fisher 1922).
