A set-of-numbers is NOT a data-set

Evans (1997) and Rees (1997) have emphasized that great care is needed to obtain good data because, otherwise, garbage in leads to garbage out. This tutorial demonstrates that, even when one has good data, the results still are incorrect if data analysis is performed incorrectly. A central issue in correct statistical analysis is determining the context within which the data arose; and resolving the inherent ambiguities in interpreting failure-data makes it essential to incorporate such a context into reliability data analyses. When this is ignored, as is usually the case (a set-of-numbers is treated as if it were an entire data-set, thus ignoring other essential information), even good data in results in garbage out.